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对象存储 BOS

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          对象存储 BOS

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          Object管理

          更新时间：2020-04-02

          上传Object

          最简单的上传

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 调用BOSClient putObject方法，可以通过如下二种方式上传Object：文件、二进制数据的形式。
            3. 对返回的BOSPutObjectResponse类型实例，可以执行获取eTag操作。

          • 示例代码

            BOSObjectContent* content = [[BOSObjectContent alloc] init];
// 以文件方式
content.objectData.file = @"<file path>";

// 或者以二进制数据方式
NSData* data = [[NSData alloc] init];
content.objectData.data = data;

BOSPutObjectRequest* request = [[BOSPutObjectRequest alloc] init];
request.bucket = @"<bucketname>";
request.key = @"<objectname>";
request.objectContent = content;

__block BOSPutObjectResponse* response = nil;
BCETask* task = [client putObject:request];
task.then(^(BCEOutput* output) {
  if (output.progress) {
      NSLog(@"put object progress is %@", output.progress);
  }

  if (output.response) {
      response = (BOSPutObjectResponse*)output.response;
      NSLog(@"put object success!");
  }

  if (output.error) {
      NSLog(@"put object failure");
  }
});
[task waitUtilFinished];

            说明：Object以文件的形式上传到BOS中，putObject函数支持不超过5GB的Object上传。在putObject请求处理成功后，BOS会在Header中返回Object的ETag作为文件标识。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSObjectContent* content = [[BOSObjectContent alloc] init];
    // 以文件方式
    content.objectData.file = @"<file path>";

    // 或者以二进制数据方式
    NSData* data = [[NSData alloc] init];
    content.objectData.data = data;

    BOSPutObjectRequest* request = [[BOSPutObjectRequest alloc] init];
    request.bucket = @"<bucketname>";
    request.key = @"<objectname>";
    request.objectContent = content;

    __block BOSPutObjectResponse* response = nil;
    BCETask* task = [client putObject:request];
    task.then(^(BCEOutput* output) {
        if (output.progress) {
            NSLog(@"put object progress is %@", output.progress);
        }

        if (output.response) {
            response = (BOSPutObjectResponse*)output.response;
            NSLog(@"put object success!");
        }

        if (output.error) {
            NSLog(@"put object failure");
        }
    });
    [task waitUtilFinished];
}

          设定Object的Http Header

          BOS支持您在上传object时设定Http Header。

          • 基本流程

            1. 创建BOSObjectMetadata类的实例。
            2. 设定BOSObjectMetadata实例的contentEncoding/contentType/contentDisposition等字段。
            3. 将BOSObjectMetadata实例设置到BOSPutObjectRequest的objectContent.metadata字段上。

          • 示例代码

            BOSObjectMetadata* metadata = [[BOSObjectMetadata alloc] init];
metadata.contentEncoding = @"<encoding>";
metadata.contentDisposition = @"<content disposition>";
content.metadata = metadata;

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSObjectContent* content = [[BOSObjectContent alloc] init];
    // 以文件方式
    content.objectData.file = @"<file path>";

    // 或者以二进制数据方式
    NSData* data = [[NSData alloc] init];
    content.objectData.data = data;

    BOSObjectMetadata* metadata = [[BOSObjectMetadata alloc] init];
    metadata.contentEncoding = @"<encoding>";
    metadata.contentDisposition = @"<content disposition>";
    content.metadata = metadata;

    BOSPutObjectRequest* request = [[BOSPutObjectRequest alloc] init];
    request.bucket = @"<bucketname>";
    request.key = @"<Objectname>";
    request.objectContent = content;

    __block BOSPutObjectResponse* response = nil;
    BCETask* task = [client putObject:request];
    task.then(^(BCEOutput* output) {
        if (output.progress) {
            NSLog(@"put object progress is %@", output.progress);
        }

        if (output.response) {
            response = (BOSPutObjectResponse*)output.response;
            NSLog(@"put object success!");
        }

        if (output.error) {
            NSLog(@"put object failure");
        }
    });
    [task waitUtilFinished];
}

          用户自定义元数据

          BOS支持用户自定义元数据来对Object进行描述。

          • 基本流程

            1. 创建BOSObjectMetadata类的实例。
            2. 将自定义元数据字典设置到BOSObjectMetadata的userMetadata字段。

          • 示例代码

            BOSObjectMetadata* metadata = [[BOSObjectMetadata alloc] init];
metadata.contentEncoding = @"<encoding>";
metadata.contentDisposition = @"<content disposition>";
content.metadata = metadata;

NSDictionary* customMetadata = @{
  @"name" : @"my-data"
};
content.metadata.userMetadata = customMetadata;

            说明：在上面代码中，用户自定义了一个名字为”name”，值为”my-data”的元数据。当用户下载此Object的时候，此元数据也可以一并得到。一个Object可以有多个类似的参数，但所有的User Meta总大小不能超过2KB。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSObjectContent* content = [[BOSObjectContent alloc] init];
    // 以文件方式
    content.objectData.file = @"<file path>";

    // 或者以二进制数据方式
    NSData* data = [[NSData alloc] init];
    content.objectData.data = data;

    BOSObjectMetadata* metadata = [[BOSObjectMetadata alloc] init];
    metadata.contentEncoding = @"<encoding>";
    metadata.contentDisposition = @"<content disposition>";
    content.metadata = metadata;

    NSDictionary* customMetadata = @{
        @"name" : @"my-data"
    };
    content.metadata.userMetadata = customMetadata;

    BOSPutObjectRequest* request = [[BOSPutObjectRequest alloc] init];
    request.bucket = @"<bucketname>";
    request.key = @"<objectname>";
    request.objectContent = content;

    __block BOSPutObjectResponse* response = nil;
    BCETask* task = [client putObject:request];
    task.then(^(BCEOutput* output) {
        if (output.progress) {
            NSLog(@"put object progress is %@", output.progress);
        }

        if (output.response) {
            response = (BOSPutObjectResponse*)output.response;
            NSLog(@"put object success!");
        }

        if (output.error) {
            NSLog(@"put object failure");
        }
    });
    [task waitUtilFinished];
}

          查看Bucket中的Object

          简单查询

          查看Bucket中Object列表。

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 执行BOSClient listObjects方法，会返回BOSListObjectsResponse类的实例。
            3. 可以对BOSListObjectsResponse类型的contents字段进行枚举，获取key/lastModified/eTag/size/owner。

          • 示例代码

            BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
listObjRequest.bucket = @"<bucketname>";

__block BOSListObjectsResponse* listObjResponse = nil;
BCETask* task = [client listObjects:listObjRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      listObjResponse = (BOSListObjectsResponse*)output.response;

      for (BOSObjectInfo* object in listObjResponse.contents) {
          NSLog(@"the object key is %@", object.key);
          NSLog(@"the object lastModified is %@", object.lastModified);
          NSLog(@"the object eTag is %@", object.eTag);
          NSLog(@"the object size is %llu", object.size);
          NSLog(@"the object owner id is %@", object.owner.ownerID);
      }
  }

  if (output.error) {
      NSLog(@"list objects failure");
  }
});
[task waitUtilFinished];

            说明： listObjects方法返回BOSListObjectsResponse对象，BOSListObjectsResponse对象包含了此次listObject请求的返回结果。用户可以通过BOSListObjectsResponse中的contents属性获取所有Object的描述信息。

            • 默认情况下，如果Bucket中的Object数量大于1000，则只会返回1000个Object，并且返回结果中isTruncated值为YES，并返回nextMarker做为下次读取的起点。
            • 若想获取更多的Object，可以使用marker参数分次读取，请参考扩展查询。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
    listObjRequest.bucket = @"<bucketname>";

    __block BOSListObjectsResponse* listObjResponse = nil;
    BCETask* task = [client listObjects:listObjRequest];
    task.then(^(BCEOutput* output) {
        if (output.response) {
            listObjResponse = (BOSListObjectsResponse*)output.response;

            for (BOSObjectInfo* object in listObjResponse.contents) {
                NSLog(@"the object key is %@", object.key);
                NSLog(@"the object lastModified is %@", object.lastModified);
                NSLog(@"the object eTag is %@", object.eTag);
                NSLog(@"the object size is %llu", object.size);
                NSLog(@"the object owner id is %@", object.owner.ownerID);
            }
        }

        if (output.error) {
            NSLog(@"list objects failure");
        }
    });
    [task waitUtilFinished];
}

          扩展查询

          用户可以通过设置BOSListObjectsResquest参数来完成更多扩展查询操作设置。BOSListObjectsResquest中可以设置的扩展参数如下：

          参数名称 说明 默认值
          maxKeys 设定此次返回Object的最大个数，不可超过1000。 1000
          prefix 设定objectKey的前缀，前缀是指objectKey包含并以prefix的值作为开始。通常与delimiter配合在查询模拟文件夹中使用。 -
          delimiter 是一个分隔符，用来对objectKey进行分层。通常与prefix配合在查询模拟文件夹中使用。从prefix开始到第一次出现delimiter字符之间的objectKey称为：commonPrefixes。 -
          marker 是一个字符串，用来设定返回结果的起始位置。设定marker值之后，返回的Object会从marker值之后按字母排序开始返回。 -

          • 基本流程

            1. 创建BOSListObjectsResquest类的实例。
            2. 设置BOSListObjectsResquest的delimiter/marker/prefix/maxKeys等字段，实现更多的扩展查询操作。
            3. 创建BOSClient类的实例，执行listObjects。

          • 示例代码

            BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
listObjRequest.bucket = @"<bucketname>";
listObjRequest.marker = @"<marker>";

__block BOSListObjectsResponse* listObjResponse = nil;
BCETask* task = [client listObjects:listObjRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      listObjResponse = (BOSListObjectsResponse*)output.response;

      for (BOSObjectInfo* object in listObjResponse.contents) {
          NSLog(@"the object key is %@", object.key);
          NSLog(@"the object lastModified is %@", object.lastModified);
          NSLog(@"the object eTag is %@", object.eTag);
          NSLog(@"the object size is %llu", object.size);
          NSLog(@"the object owner id is %@", object.owner.ownerID);
      }
  }

  if (output.error) {
      NSLog(@"list objects failure");
  }
});
[task waitUtilFinished];

          • 完整示例

            示例一：

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
    listObjRequest.bucket = @"<bucketname>";
    listObjRequest.marker = @"<marker>";

    __block BOSListObjectsResponse* listObjResponse = nil;
    BCETask* task = [client listObjects:listObjRequest];
    task.then(^(BCEOutput* output) {
        if (output.response) {
            listObjResponse = (BOSListObjectsResponse*)output.response;

            for (BOSObjectInfo* object in listObjResponse.contents) {
                NSLog(@"the object key is %@", object.key);
                NSLog(@"the object lastModified is %@", object.lastModified);
                NSLog(@"the object eTag is %@", object.eTag);
                NSLog(@"the object size is %llu", object.size);
                NSLog(@"the object owner id is %@", object.owner.ownerID);
            }
        }

        if (output.error) {
            NSLog(@"list objects failure");
        }
    });
    [task waitUtilFinished];
}

            示例二：使用nextMarker的完整示例。

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
    listObjRequest.bucket = @"<bucketname>";
    listObjRequest.marker = @"<marker>";

    __block BOSListObjectsResponse* listObjResponse = nil;
    BCETask* task = [client listObjects:listObjRequest];
    task.then(^(BCEOutput* output) {
        if (output.response) {
            listObjResponse = (BOSListObjectsResponse*)output.response;
        }

        if (output.error) {
            NSLog(@"list objects failure");
        }
    });
    [task waitUtilFinished];

    if (listObjResponse != nil) {
        listObjRequest.marker = listObjResponse.nextMarker;
        task = [client listObjects:listObjRequest];
        task.then(^(BCEOutput* output) {
            if (output.response) {
                listObjResponse = (BOSListObjectsResponse*)output.response;

                for (BOSObjectInfo* object in listObjResponse.contents) {
                    NSLog(@"the object key is %@", object.key);
                    NSLog(@"the object lastModified is %@", object.lastModified);
                    NSLog(@"the object eTag is %@", object.eTag);
                    NSLog(@"the object size is %llu", object.size);
                    NSLog(@"the object owner id is %@", object.owner.ownerID);
                }
            }
        });
    }
}

          查询模拟文件夹

          由于BOS本身是一个(<Key>,<Value>)的存储系统，所以原则上并不会存在“文件夹”的概念，但您可以通过delimiter和prefix参数的配合进行文件夹功能模拟。

          假设Bucket中有5个文件：bos.jpg，fun/，fun/test.jpg，fun/movie/001.avi，fun/movie/007.avi，可以把 “/” 符号作为分隔符模拟文件夹。

          递归列出模拟文件夹下所有文件

          可以通过设置prefix参数来获取某个模拟文件夹下所有的文件：

          BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
listObjRequest.bucket = @"<bucketname>";
 listObjRequest.prefix = @"fun/";

__block BOSListObjectsResponse* listObjResponse = nil;
BCETask* task = [client listObjects:listObjRequest];
task.then(^(BCEOutput* output) {
    if (output.response) {
        listObjResponse = (BOSListObjectsResponse*)output.response;

        for (BOSObjectInfo* object in listObjResponse.contents) {
            NSLog(@"%@", object.key);
        }
    }
});
[task waitUtilFinished];

          输出：

          Objects:
fun/
fun/movie/001.avi
fun/movie/007.avi
fun/test.jpg

          查看模拟文件夹下的文件和子文件夹

          在prefix和delimiter结合的情况下，可以列出模拟文件夹下的文件和子文件夹：

          BOSListObjectsRequest* listObjRequest = [[BOSListObjectsRequest alloc] init];
listObjRequest.bucket = @"<bucketname>";

// 指定"/"为模拟文件夹的分隔符
listObjRequest.delimiter = @"/";

// 列出fun文件夹下的所有文件和子文件夹
listObjRequest.prefix = @"fun/";

__block BOSListObjectsResponse* listObjResponse = nil;
BCETask* task = [client listObjects:listObjRequest];
task.then(^(BCEOutput* output) {
    if (output.response) {
        listObjResponse = (BOSListObjectsResponse*)output.response;
    }

    if (output.error) {
        NSLog(@"list objects failure");
    }
});
[task waitUtilFinished];

// 遍历所有Object
NSLog(@"Objects:");
for (BOSObjectInfo* object in listObjResponse.contents) {
    NSLog(@"%@", object.key);
}

// 遍历所有CommonPrefix
NSLog(@"CommonPrefixs:");
for (NSString* commonPrefix in listObjResponse.commonPrefixes) {
    NSLog(@"%@", commonPrefix);
}

          输出：

          Objects:
fun/
fun/test.jpg

CommonPrefixs:
fun/movie/

          说明： 返回的结果中，contents的列表中给出的是fun文件夹下的文件。而commonPrefixs的列表中给出的是fun文件夹下的所有子文件夹。可以看出fun/movie/001.avi，fun/movie/007.avi两个文件并没有被列出来，因为它们属于fun文件夹下的movie子文件夹下的文件。

          获取Object

          简单的获取Object

          用户可以通过如下代码将Object读取到内存中。

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 执行BOSClient getObject方法，会返回BOSGetObjectResponse实例。
            3. 访问BOSGetObjectResponse示例的objectContent.objectData.data属性，获取数据。

          • 示例代码

            __block BOSGetObjectResponse* getObjResponse = nil;
BOSGetObjectRequest* getObjRequest = [[BOSGetObjectRequest alloc] init];
getObjRequest.bucket = @"<bucketname>";
getObjRequest.key = @"<objectname>";
BCETask* task = [client getObject:getObjRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      getObjResponse = (BOSGetObjectResponse*)output.response;
      NSLog(@"get object success!");
  }

  if (output.error) {
      NSLog(@"get object failure with %@", outpu****t.error);
  }

  if (output.progress) {
      NSLog(@"the get object progress is %@", output.progress);
  }
});
[task waitUtilFinished];

// 获取内存中的数据
NSData* data = getObjResponse.objectContent.objectData.data;

            注意：

            • BOSObjectContent中包含了Object的各种信息，包含Object所在的Bucket、Object的名称、MetaData以及数据存储。
            • BOSObjectMetadata中包含了Object上传时定义的ETag，Http Header以及自定义的元数据。
            • 通过BOSObjectContent的objectData属性，获取到Object的数据。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    __block BOSGetObjectResponse* getObjResponse = nil;
    BOSGetObjectRequest* getObjRequest = [[BOSGetObjectRequest alloc] init];
    getObjRequest.bucket = @"<bucketname>";
    getObjRequest.key = @"<objectname>";
    BCETask* task = [client getObject:getObjRequest];
    task.then(^(BCEOutput* output) {
        if (output.response) {
            getObjResponse = (BOSGetObjectResponse*)output.response;
            NSLog(@"get object success!");
        }

        if (output.error) {
            NSLog(@"get object failure with %@", output.error);
        }

        if (output.progress) {
            NSLog(@"the get object progress is %@", output.progress);
        }
    });
    [task waitUtilFinished];

    NSData* data = getObjResponse.objectContent.objectData.data;
}

          下载Object的一部分内容

          • 基本流程

            1. 创建BOSGetObjectRequest类的实例。
            2. BOSGetObjectRequestt实例的rangeStart和/或rangeEnd字段。
            3. 执行client getObject操作。

          • 示例代码

            __block BOSGetObjectResponse* getObjResponse = nil;
BOSGetObjectRequest* getObjRequest = [[BOSGetObjectRequest alloc] init];
getObjRequest.bucket = @"<bucketname>";
getObjRequest.key = @"<objectname>";

// 获取前100个字节
getObjRequest.rangeStart = @"0";
getObjRequest.rangeStart = @"99";

BCETask* task = [client getObject:getObjRequest];
task.then(^(BCEOutput* output) {
    if (output.response) {
        getObjResponse = (BOSGetObjectResponse*)output.response;
        NSLog(@"get object success!");
    }

    if (output.error) {
        NSLog(@"get object failure with %@", output.error);
    }

    if (output.progress) {
        NSLog(@"the get object progress is %@", output.progress);
    }
});
[task waitUtilFinished];

NSData* data = getObjResponse.objectContent.objectData.data;

            说明：用户可以用此功能实现文件的分段下载和断点续传。

          下载Object到指定路径

          用户可以通过如下代码直接将Object下载到指定路径。

          • 基本流程

            1. 创建BOSGetObjectRequest类的实例。
            2. 设置要保存的文件名到BOSGetObjectRequest实例的file字段。
            3. 执行client getObject操作。
            4. Object可以直接下载到指定路径。

          • 示例代码

            __block BOSGetObjectResponse* getObjResponse = nil;
BOSGetObjectRequest* getObjRequest = [[BOSGetObjectRequest alloc] init];
getObjRequest.bucket = @"<bucketname>";
getObjRequest.key = @"<objectname>";

// 设置保存到的文件路径
getObjRequest.file = @"<file>";

BCETask* task = [client getObject:getObjRequest];
task.then(^(BCEOutput* output) {
    if (output.response) {
        getObjResponse = (BOSGetObjectResponse*)output.response;
        NSLog(@"get object success!");
    }

    if (output.error) {
        NSLog(@"get object failure with %@", output.error);
    }

    if (output.progress) {
        NSLog(@"the get object progress is %@", output.progress);
    }
});
[task waitUtilFinished];

          获取Object的storageClass

          Object的storage class属性分为STANDARD(标准存储), STANDARD_IA(低频存储)和COLD(冷存储)。

          示例代码

          __block BOSGetObjectMetadataResponse* getObjMetaResponse = nil;
BCETask* task = [client getObjectMetadata:@"<bucketname>" objectKey:@"<objectname>"];
task.then(^(BCEOutput* output) {
    if (output.response) {
        getObjMetaResponse = (BOSGetObjectMetadataResponse*)output.response;
        NSString storageClass = getObjMetaResponse.storageClass;
        NSLog(@"get object storageClass success!");
    }

    if (output.error) {
        NSLog(@"get object storageClass failure");
    }
});
[task waitUtilFinished];

          只获取ObjectMetadata

          通过getObjectMetadata 方法可以只获取 Object metadata 而不获取Object的实体。

          • 示例代码

            __block BOSGetObjectMetadataResponse* getObjMetaResponse = nil;
BCETask* task = [client getObjectMetadata:@"<bucketname>" objectKey:@"<objectname>"];
task.then(^(BCEOutput* output) {
    if (output.response) {
        getObjMetaResponse = (BOSGetObjectMetadataResponse*)output.response;
        NSLog(@"get object metadata success!");
    }

    if (output.error) {
        NSLog(@"get object metadata failure");
    }
});
[task waitUtilFinished];

          获取Object的URL

          您可以通过如下代码获取指定Object的URL，该功能通常用于您将Object的URL临时分享给其他用户的场景。

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 执行BOSClient generatePresignedUrl方法。
            3. 返回一个Object的URL。

          • 示例代码

            __block BOSGeneratePresignedUrlResponse *generateObjetUrlRes = nil;
  BCEOutput_ output = [client generatePresignedUrl:@"<bucketname>" objectKey:@"<objectname>" expirationInSeconds:<ExpirationInSeconds>];
  if (output.response) {
      generateObjetUrlRes = (BOSGeneratePresignedUrlResponse_)output.response;
      NSLog(@"get url success, the usrlstting is : %@", [generateObjetUrlRes.objectUrl absoluteString]);
  }
  if (output.error) {
      NSLog(@"get url failure, error : %@:", output.error);
  }

          说明： ExpirationInSeconds为指定的URL有效时长，时间从当前时间算起，为可选参数，不配置时系统默认值为1800秒。如果要设置为永久不失效的时间，可以将ExpirationInSeconds参数设置为 -1，不可设置为其他负数。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    __block BOSGeneratePresignedUrlResponse *generateObjetUrlRes = nil;
      BCEOutput* output = [client generatePresignedUrl:@"<bucketname>" objectKey:@"<objectname>" expirationInSeconds:<ExpirationInSeconds>];
    if (output.response) {
    generateObjetUrlRes = 	(BOSGeneratePresignedUrlResponse*)output.response;
    NSLog(@"get url success, the usrlstting is : %@", [generateObjetUrlRes.objectUrl absoluteString]);
    }
    if (output.error) {
    NSLog(@"get url failure, error : %@:", output.error);
    }
}

          删除Object

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 执行BOSClient deleteObject方法。
            3. 若操作失败后产生错误。

          • 示例代码

            __block BOSDeleteObjectResponse* response = nil;
BCETask* task = [client deleteObject:@"<bucketname>" objectKey:@"<objectname>"];
task.then(^(BCEOutput* output) {
    if (output.response) {
        response = (BOSDeleteObjectResponse*)output.response;
        NSLog(@"delete obj success!");
    }

    if (output.error) {
        NSLog(@"delete obj failure");
    }
});
[task waitUtilFinished];

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    __block BOSDeleteObjectResponse* response = nil;
    BCETask* task = [client deleteObject:@"<bucketname>" objectKey:@"<objectname>"];
    task.then(^(BCEOutput* output) {
      if (output.response) {
          response = (BOSDeleteObjectResponse*)output.response;
          NSLog(@"delete obj success!");
      }

      if (output.error) {
          NSLog(@"delete obj failure");
      }
    });
    [task waitUtilFinished];
}

          拷贝Object

          简单拷贝Object

          • 基本流程

            1. 创建BOSClient类的实例。
            2. 执行BOSClient copyObject方法。
            3. 返回BOSCopyObjectResponse类实例，可通过eTag/lastModified等属性获取eTag和最后修改时间。

          • 示例代码

            BOSCopyObjectRequest* request = [[BOSCopyObjectRequest alloc] init];
request.bucket = @"<bucketname>";
request.key = @"<objectname>";
request.source = @"<sourceBucket>/<sourceObject";

__block BOSCopyObjectResponse* response = nil;
BCETask* task = [client copyObject:request];
task.then(^(BCEOutput* output) {
    if (output.response) {
        response = (BOSCopyObjectResponse*)output.response;
        NSLog(@"copy obj success!");
    }

    if (output.error) {
        NSLog(@"copy obj failure");
    }
});
[task waitUtilFinished];

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSCopyObjectRequest* request = [[BOSCopyObjectRequest alloc] init];
    request.bucket = @"<bucketname>";
    request.key = @"<objectname>";
    request.source = @"<sourceBucket>/<sourceObject";

    __block BOSCopyObjectResponse* response = nil;
    BCETask* task = [client copyObject:request];
    task.then(^(BCEOutput* output) {
      if (output.response) {
          response = (BOSCopyObjectResponse*)output.response;
          NSLog(@"copy obj success!");
      }

      if (output.error) {
          NSLog(@"copy obj failure");
      }
    });
    [task waitUtilFinished];
}

            说明：copyObject 方法返回一个 BOSCopyObjectResponse 对象，该对象中包含了新Object的ETag和修改时间。

          指定条件拷贝Object

          您也可以通过指定条件来实现Object的拷贝。该功能一般用于如下场景：

          • Copy一个Object但重新设置meta。
          • 重置某个现有Object的meta（把源和目标设置为同一个Object）。
          • 当源Object的eTag与指定的eTag相同时复制；
          • 当源Object的eTag与指定的eTag不相同时复制；
          • 当源Object的在指定的时间后没有被修改时复制；
          • 当源Object的在指定的时间后被修改过时复制；

          具体内容如下：

          • 基本流程

            1. 创建BOSCopyObjectRequest类的实例，传入<source>,<ifMatchEtag>, <ifNotMatchEtag>,<ifModifiedSince>,<ifUnmodifiedSince>, <metadataDirective>参数。
            2. 返回BOSCopyObjectResponse类实例，可通过eTag/lastModified属性获取eTag和最后修改时间。

          • 示例代码

            BOSCopyObjectRequest* request = [[BOSCopyObjectRequest alloc] init];
request.bucket = @"<bucketname>";
request.key = @"<objectname>";
request.source = @"<sourceBucket>/<sourceObject";
request.metadataDirective = @"replace";
request.ifModifiedSince = @"Wed, 01 Mar 2006 12:00:00 GMT";

__block BOSCopyObjectResponse* response = nil;
BCETask* task = [client copyObject:request];
task.then(^(BCEOutput* output) {
  if (output.response) {
      response = (BOSCopyObjectResponse*)output.response;
      NSLog(@"copy obj success!");
  }

  if (output.error) {
      NSLog(@"copy obj failure");
  }
});
[task waitUtilFinished];

            说明：BOSCopyObjectRequest 允许用户修改目的Object的ObjectMeta，同时也提供 MatchingETagConstraints 参数的设定。

          Object的分块上传

          除了通过putObject()方法上传文件到BOS以外，BOS还提供了另外一种上传模式：分块上传（Multipart Upload）。用户可以在如下的应用场景内（但不仅限于此），使用分块上传模式，如：

          • 需要支持断点上传。
          • 上传超过5GB大小的文件。
          • 网络条件较差，和BOS的服务器之间的连接经常断开。
          • 需要流式地上传文件。
          • 上传文件之前，无法确定上传文件的大小。

          分块完成Multipart Upload

          假设有一个文件，本地路径为/path/to/file.zip，由于文件比较大，使用分块上传其传输到BOS中。

          • 基本流程

            1. 初始化Multipart Upload。
            2. 上传分块。
            3. 完成分块上传。

          初始化Multipart Upload

          使用initiateMultipartUpload方法来初始化一个分块上传事件：

          • 示例代码

            BOSInitiateMultipartUploadRequest* initMPRequest = [[BOSInitiateMultipartUploadRequest alloc] init];
initMPRequest.bucket = @"<bucketname>";
initMPRequest.key = @"<objectname>";
initMPRequest.contentType = @"<content type>";

__block BOSInitiateMultipartUploadResponse* initMPResponse = nil;
BCETask* task = [client initiateMultipartUpload:initMPRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      initMPResponse = (BOSInitiateMultipartUploadResponse*)output.response;
      NSLog(@"initiate multipart upload success!");
  }

  if (output.error) {
      NSLog(@"initiate multipart upload failure");
  }
});
[task waitUtilFinished];

NSString* uploadID = initMPResponse.uploadId;

            说明：initiateMultipartUpload的返回结果中含有uploadId，它是区分分块上传事件的唯一标识，在后面的操作中，我们将用到它。

          上传分块

          将文件分块上传。

          • 示例代码

            // 计算分块个数
NSString* file = @"/path/to/file.zip";
NSDictionary<NSString*, id>* attr = [[NSFileManager defaultManager] attributesOfItemAtPath:file error:nil];
uint64_t fileSize = attr.fileSize;
uint64_t partSize = 1024 * 1024 * 5L;
uint64_t partCount = fileSize / partSize;
if (fileSize % partSize != 0) {
  ++partCount;
}

NSMutableArray<BOSPart*>* parts = [NSMutableArray array];
NSFileHandle* handle = [NSFileHandle fileHandleForReadingAtPath:@"/path/to/file.zip"];
for (uint64_t i = 0; i < partCount; ++i) {
  // seek
  uint64_t skip = partSize * i;
  [handle seekToFileOffset:skip];
  uint64_t size = (partSize < fileSize - skip) ? partSize : fileSize - skip;

  // data
  NSData* data = [handle readDataOfLength:size];

  // request
  BOSUploadPartRequest* uploadPartRequest = [[BOSUploadPartRequest alloc] init];
  uploadPartRequest.bucket = @"<bucketname>";
  uploadPartRequest.key = @"<objectname>";
  uploadPartRequest.objectData.data = data;
  uploadPartRequest.partNumber = i + 1;
  uploadPartRequest.uploadId = uploadID;

  __block BOSUploadPartResponse* uploadPartResponse = nil;
  task = [client uploadPart:uploadPartRequest];
  task.then(^(BCEOutput* output) {
      if (output.response) {
          uploadPartResponse = (BOSUploadPartResponse*)output.response;
          BOSPart* part = [[BOSPart alloc] init];
          part.partNumber = i + 1;
          part.eTag = uploadPartResponse.eTag;
                  [parts addObject:part];
      }
  });
  [task waitUtilFinished];
}

            注意：上面代码的核心是调用uploadPart方法来上传每一个分块，但是要注意以下几点：

            • uploadPart方法要求除最后一个Part以外，其他的Part大小都要大于等于5MB。但是Upload Part接口并不会立即校验上传Part的大小；只有当Complete Multipart Upload的时候才会校验。
            • 为了保证数据在网络传输过程中不出现错误，建议您在uploadPart后，使用每个分块BOS返回的Content-MD5值分别验证已上传分块数据的正确性。当所有分块数据合成一个Object后，不再含MD5值。
            • Part号码的范围是1~10000。如果超出这个范围，BOS将返回InvalidArgument的错误码。
            • 每次上传Part时都要把流定位到此次上传块开头所对应的位置。
            • 每次上传Part之后，BOS的返回结果会包含一个BOSPart对象，它是上传块的ETag与块编号（PartNumber）的组合，在后续完成分块上传的步骤中会用到它，因此需要将其保存起来。一般来讲这些BOSPart对象将被保存到数组中。

          完成分块上传

          • 示例代码

            BOSCompleteMultipartUploadRequest* compMultipartRequest = [[BOSCompleteMultipartUploadRequest alloc] init];
compMultipartRequest.bucket = @"<bucketname>";
compMultipartRequest.key = @"<objectname>";
compMultipartRequest.uploadId = uploadID;
compMultipartRequest.parts = parts;

__block BOSCompleteMultipartUploadResponse* complResponse = nil;
task = [client completeMultipartUpload:compMultipartRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      complResponse = (BOSCompleteMultipartUploadResponse*)output.response;
      NSLog(@"complte multiparts success!");
  }

  if (output.error) {
      NSLog(@"complte multiparts failure %@", output.error);
  }
});
[task waitUtilFinished];

            说明：上面代码中的 parts 是第二步中保存的parts的列表，BOS收到用户提交的Part列表后，会逐一验证每个数据Part的有效性。当所有的数据Part验证通过后，BOS将把这些数据part组合成一个完整的Object。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
// 初始化
BCECredentials* credentials = [[BCECredentials alloc] init];
credentials.accessKey = @"<access key>";
credentials.secretKey = @"<secret key>";
BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
configuration.credentials = credentials;

BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

// 初始化分块上传
BOSInitiateMultipartUploadRequest* initMPRequest = [[BOSInitiateMultipartUploadRequest alloc] init];
initMPRequest.bucket = @"<bucketname>";
initMPRequest.key = @"<objectname>";
initMPRequest.contentType = @"<content type>";

 __block BOSInitiateMultipartUploadResponse* initMPResponse = nil;
 BCETask* task = [client initiateMultipartUpload:initMPRequest];
 task.then(^(BCEOutput* output) {
     if (output.response) {
         initMPResponse = (BOSInitiateMultipartUploadResponse*)output.response;
         NSLog(@"initiate multipart upload success!");
     }

     if (output.error) {
         NSLog(@"initiate multipart upload failure");
     }
 });
 [task waitUtilFinished];

 NSString* uploadID = initMPResponse.uploadId;

 // 计算分块个数
 NSString* file = @"/path/to/file.zip";
 NSDictionary<NSString*, id>* attr = [[NSFileManager defaultManager] attributesOfItemAtPath:file error:nil];
 uint64_t fileSize = attr.fileSize;
 uint64_t partSize = 1024 * 1024 * 5L;
 uint64_t partCount = fileSize / partSize;
 if (fileSize % partSize != 0) {
     ++partCount;
 }

 NSMutableArray<BOSPart*>* parts = [NSMutableArray array];

 NSFileHandle* handle = [NSFileHandle fileHandleForReadingAtPath:@"/path/to/file.zip"];
 for (uint64_t i = 0; i < partCount; ++i) {
     // seek
     uint64_t skip = partSize * i;
     [handle seekToFileOffset:skip];
     uint64_t size = (partSize < fileSize - skip) ? partSize : fileSize - skip;

     // data
     NSData* data = [handle readDataOfLength:size];

     // request
     BOSUploadPartRequest* uploadPartRequest = [[BOSUploadPartRequest alloc] init];
     uploadPartRequest.bucket = @"<bucketname>";
     uploadPartRequest.key = @"<objectname>";
     uploadPartRequest.objectData.data = data;
     uploadPartRequest.partNumber = i + 1;
     uploadPartRequest.uploadId = uploadID;

     __block BOSUploadPartResponse* uploadPartResponse = nil;
     task = [client uploadPart:uploadPartRequest];
     task.then(^(BCEOutput* output) {
         if (output.response) {
             uploadPartResponse = (BOSUploadPartResponse*)output.response;
             BOSPart* part = [[BOSPart alloc] init];
             part.partNumber = i + 1;
             part.eTag = uploadPartResponse.eTag;
                     [parts addObject:part];
         }
     });
     [task waitUtilFinished];
 }

 BOSCompleteMultipartUploadRequest* compMultipartRequest = [[BOSCompleteMultipartUploadRequest alloc] init];
 compMultipartRequest.bucket = @"<bucketname>";
 compMultipartRequest.key = @"<objectname>";
 compMultipartRequest.uploadId = uploadID;
 compMultipartRequest.parts = parts;

 __block BOSCompleteMultipartUploadResponse* complResponse = nil;
 task = [client completeMultipartUpload:compMultipartRequest];
 task.then(^(BCEOutput* output) {
     if (output.response) {
         complResponse = (BOSCompleteMultipartUploadResponse*)output.response;
         NSLog(@"complte multiparts success!");
     }

     if (output.error) {
         NSLog(@"complte multiparts failure %@", output.error);
     }
 });
 [task waitUtilFinished];
}

          取消分块上传

          用户可以使用abortMultipartUpload方法取消分块上传。

          • 示例代码

            BOSAbortMultipartUploadRequest* abortRequest = [[BOSAbortMultipartUploadRequest alloc] init];
abortRequest.bucket = @"bucket";
abortRequest.key = @"<objectname>";
abortRequest.uploadId = uploadID;

__block BOSAbortMultipartUploadResponse* abortResponse = nil;
task = [client abortMultipartUpload:abortRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      abortResponse = (BOSAbortMultipartUploadResponse*)output.response;
      NSLog(@"abort multiparts success!");
  }

  if (output.error) {
      NSLog(@"abort multiparts failure %@", output.error);
  }
});
[task waitUtilFinished];

          获取未完成的分块上传

          用户可以使用listMultipartUploads方法获取Bucket内未完成的分块上传事件。

          • 基本流程

            1. 创建BOSListMultipartUploadsRequest类的实例,传入<BucketName>参数。
            2. 创建BOSClient类的实例,执行BOSClient listMultipartUploads方法。
            3. listMultipartUploads返回所有未完成的分块上传信息。

          • 示例代码

            BOSListMultipartUploadsRequest* listMultipartRequest = [[BOSListMultipartUploadsRequest alloc] init];
listMultipartRequest.bucket = @"<bucketname>";

__block BOSListMultipartUploadsResponse* listMultipartResponse = nil;
task = [client listMultipartUploads:listMultipartRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      listMultipartResponse = (BOSListMultipartUploadsResponse*)output.response;
      NSLog(@"list multipart success");
  }

  if (output.error) {
      NSLog(@"list multipart failure %@", output.error);
  }
});
[task waitUtilFinished];

            注意：

            • 默认情况下，如果Bucket中的分块上传事件的数目大于1000，则只会返回1000个Object，并且返回结果中IsTruncated的值为True，同时返回nextKeyMarker作为下次读取的起点。
            • 若想获取更多分块上传事件，可以使用keyMarker参数分次读取。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSListMultipartUploadsRequest* listMultipartRequest = [[BOSListMultipartUploadsRequest alloc] init];
    listMultipartRequest.bucket = @"<bucketname>";

    __block BOSListMultipartUploadsResponse* listMultipartResponse = nil;
    BCETask* task = [client listMultipartUploads:listMultipartRequest];
    task.then(^(BCEOutput* output) {
      if (output.response) {
          listMultipartResponse = (BOSListMultipartUploadsResponse*)output.response;
          NSLog(@"list multipart success");
      }

      if (output.error) {
          NSLog(@"list multipart failure %@", output.error);
      }
    });
    [task waitUtilFinished];

    for (BOSMultipartUpload* upload in listMultipartResponse.uploads) {
        NSLog(@"upload id : %@", upload.uploadId);
    }
}

          获取所有已上传的分块信息

          用户可以使用listParts方法获取某个上传事件中所有已上传的块。

          • 基本流程

            1. 创建BOSListPartsRequest类的实例,传入<BucketName>,<ObjectKey>, <UploadId>参数。
            2. 创建BOSClient类的实例,执行BOSClient listParts方法。
            3. listParts返回所有已上传part的信息。

          • 示例代码

            BOSListPartsRequest* listPartsRequest = [[BOSListPartsRequest alloc] init];
listPartsRequest.bucket = @"<bucketname>";
listPartsRequest.key = @"<objectname>";
listPartsRequest.uploadId = @"<upload id>";;

__block BOSListPartsResponse* listPartsResponse = nil;
BCETask* task = [client listParts:listPartsRequest];
task.then(^(BCEOutput* output) {
  if (output.response) {
      listPartsResponse = (BOSListPartsResponse*)output.response;
      NSLog(@"list parts success!");
  }

  if (output.error) {
      NSLog(@"list part failure %@", output.error);
  }
});
[task waitUtilFinished];

for (BOSPart* part in listPartsResponse.parts) {
    NSLog(@"part etag %@", part.eTag);
}

            注意：

            • 默认情况下，如果Bucket中的分块上传事件的数目大于1000，则只会返回1000个Object，并且返回结果中IsTruncated的值为True，同时返回NextPartNumberMarker作为下次读取的起点。
            • 若想获取更多已上传的分块信息，可以使用PartNumberMarker参数分次读取。

          • 完整示例

            #import <BaiduBCEBasic/BaiduBCEBasic.h>
#import <BaiduBCEBOS/BaiduBCEBOS.h>

void example(void) {
    // 初始化
    BCECredentials* credentials = [[BCECredentials alloc] init];
    credentials.accessKey = @"<access key>";
    credentials.secretKey = @"<secret key>";
    BOSClientConfiguration* configuration = [[BOSClientConfiguration alloc] init];
    configuration.credentials = credentials;

    BOSClient* client = [[BOSClient alloc] initWithConfiguration:configuration];

    BOSListPartsRequest* listPartsRequest = [[BOSListPartsRequest alloc] init];
    listPartsRequest.bucket = @"<bucketname>";
    listPartsRequest.key = @"<objectname>";
    listPartsRequest.uploadId = @"<upload id>";;

    __block BOSListPartsResponse* listPartsResponse = nil;
    BCETask* task = [client listParts:listPartsRequest];
    task.then(^(BCEOutput* output) {
    if (output.response) {
        listPartsResponse = (BOSListPartsResponse*)output.response;
        NSLog(@"list parts success!");
    }

    if (output.error) {
        NSLog(@"list part failure %@", output.error);
    }
    });
    [task waitUtilFinished];

    for (BOSPart* part in listPartsResponse.parts) {
        NSLog(@"part etag %@", part.eTag);
    }
}
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