Support custom packet size and delay in MultipartForm uploads

[chiseller]

In AFNetworking we can upload a file custom packet size and delay time like this
throttleBandwidthWithPacketSize:(NSUInteger)numberOfBytes delay:(NSTimeInterval)delay;
but how can i do with Alamofire?thanks!

[jshier]

There is no equivalent in Alamofire, as it does not use streams for uploads. It's unlikely we'd ever add support for this, but what's your use case?

[chiseller]

hi jishier，thanks for response。Our server needs to limit the form data packet to 2kb when uploading files, and the time interval for each write is 100ms. In AFNetworking, I can set up like this：

    AFHTTPSessionManager *up = [AFHTTPSessionManager manager];
    NSString *url = "";
    [up POST:url parameters:nil headers: nil constructingBodyWithBlock:^(id<AFMultipartFormData>  _Nonnull formData) {
        [formData appendPartWithFileURL:path name:path.absoluteString error:&errors];
        //write stream 2kb each 100ms
        [formData throttleBandwidthWithPacketSize:2048 delay:0.1];
    } progress:^(NSProgress * _Nonnull uploadProgress) {
        //do something
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        //do something
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        //do something
    }];

[jshier]

You can get the same functionality by creating your own OutputStream with the appropriate settings, which you then use with upload directly. If you need multipart encoding, you'd have to do that manually as well. Since Alamofire doesn't use streams most of the time, it's unlikely we'll add native support.

[chiseller]

hey @jshier ，i find source code in MultipartFormData.swift, in BodyPart class i find InputStream,so i think that i can subclass MultipartFormData ,then custom InputStream write progress and delay time?

[jshier]

Good point. This needs a bit more investigation.