用AFNetworking上传文件到node.js server

前几天做了一个上传文件的特性，ios端使用的是AFNetworking组件，server端是express

客户端代码：

AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:[NSURL URLWithString:UPLOAD_BACKUP_FILE_SERVICE_URL]];
    
    NSDictionary *headers = @{@"Authorization":[NSString stringWithFormat:@"Bearer %@",token], @"custom-enterpriseId":enterpriseId};
    
    for(NSString *zipFileName in sorted){
        
        NSString *zipFilePath = [[YLSGlobalUtils getCurrentEnterpriseDirPath] stringByAppendingPathComponent:zipFileName];
        NSData *zipData = [NSData dataWithContentsOfFile:zipFilePath];
        
        void (^constructingBlock)(id<AFMultipartFormData>)  = ^(id<AFMultipartFormData> formData) {
            [formData appendPartWithFileData:zipData name:@"file" fileName:zipFileName mimeType:@"application/zip"];
        };
        
        void (^successBlock)(AFHTTPRequestOperation*, id) = ^(AFHTTPRequestOperation *operation, id responseObject) {
            NSLog(@"Success: %@ ***** %@", operation.responseString, responseObject);
            [fileManager removeItemAtPath:zipFilePath error:nil];
            [self addBackupRecord];
        };
        
        void (^failureBlock)(AFHTTPRequestOperation*, NSError*) = ^(AFHTTPRequestOperation *operation, NSError *error) {
            NSLog(@"Error: %@ ***** %@", operation.responseString, error);
            int code = [error code];
            if(3840 == code || -1001 == code){// 3840和-1001错误码小概率出现，文件上传已成功
                [fileManager removeItemAtPath:zipFilePath error:nil];
                [self addBackupRecord];
            }
        };

        AFHTTPRequestOperation *operation = [manager POST:UPLOAD_BACKUP_FILE_SERVICE_URL parameters:headers constructingBodyWithBlock:constructingBlock success:successBlock failure:failureBlock];
        [operation start];
    }

关键在于constructingBlock那个块，里面的name参数要传@"file"，与server端的代码对应，server端有以下代码：

req.files.file.path;
req.files.file.name;

req.files.file对象是express包装的，path属性在express里配置：

app.use(express.bodyParser({
                uploadDir: __dirname + '/../var/uploads',
                keepExtensions: true,
                limit: 10000000,
                defer: true
            }));

file.path取的就是uploadDir的值，file.name的值从client传过来，也就是client代码里的name参数

另外，AFNetworking的API，会自动设置boundary，用chunk上传文件，不需要手工编码