RestSharp AddFile Using Stream

问题

I am using RestSharp (version 105.2.3.0 in Visual Studio 2013, .net 4.5) to call a NodeJS hosted webservice. One of the calls I need to make is to upload a file. Using a RESTSharp request, if I retrieve the stream from my end into a byte array and pass that to AddFile, it works fine. However, I would much rather stream the contents and not load up entire files in server memory (the files can be 100's of MB).

If I set up an Action to copy my stream (see below), I get an exception at the "MyStream.CopyTo" line of System.Net.ProtocolViolationException (Bytes to be written to the stream exceed the Content-Length bytes size specified). This exception is thrown within the Action block after client.Execute is called.

From what I read, I should not be manually adding a Content-Length header, and it doesn't help if I do. I have tried setting CopyTo buffer too small and large values, as well as omitting it entirely, to no avail. Can somebody give me a hint on what I've missed?

    // Snippet...
    protected T PostFile<T>(string Resource, string FieldName, string FileName,
        string ContentType, Stream MyStream, 
        IEnumerable<Parameter> Parameters = null) where T : new()
    {
        RestRequest request = new RestRequest(Resource);
        request.Method = Method.POST;

        if (Parameters != null)
        {
            // Note:  parameters are all UrlSegment values
            request.Parameters.AddRange(Parameters);
        }

        // _url, _username and _password are defined configuration variables
        RestClient client = new RestClient(_url);
        if (!string.IsNullOrEmpty(_username))
        {
            client.Authenticator = new HttpBasicAuthenticator(_username, _password);
        }

        /*
        // Does not work, throws System.Net.ProtocolViolationException,
        // Bytes to be written to the stream exceed the 
        // Content-Length bytes size specified.
        request.AddFile(FieldName, (s) =>
        {
            MyStream.CopyTo(s);
            MyStream.Flush();
        }, FileName, ContentType);
        */

        // This works, but has to load the whole file in memory
        byte[] data = new byte[MyStream.Length];
        MyStream.Read(data, 0, (int) MyStream.Length);
        request.AddFile(FieldName, data, FileName, ContentType);

        var response = client.Execute<T>(request);

        // check response and continue...
    }

回答1:

I had the same issue. I ended up using the .Add() on the Files collection. It has a FileParameter param which has the same params as AddFile(), you just have to add the ContentLength:

var req = GetRestRequest("Upload", Method.POST, null);
//req.AddFile("file",
//    (s) => {
//        var stream = input(imageObject);
//        stream.CopyTo(s);
//        stream.Dispose();
//    },
//    fileName, contentType);

req.Files.Add(new FileParameter {
    Name = "file",
    Writer = (s) => {
        var stream = input(imageObject);
        stream.CopyTo(s);
        stream.Dispose();
    },
    FileName = fileName,
    ContentType = contentType,
    ContentLength = contentLength
});

回答2:

The following code works for me for uploading a csv file using rest sharp. Web services API has been called.

var client = new RestClient(<YOUR API END URL >);
var request = new RestRequest(Method.POST) ;
request.AlwaysMultipartFormData = true;
request. AddHeader("Content-Type", "multipart/form-data");
request.AddHeader("X-API-TOKEN", <Your Unique Token - again not needed for certain calls>);
request.AddParameter(<Your parameters.....>);
request.AddFile("file", currentFileLocation, contentType);
request.AddParameter("multipart/form-data", fileName, ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
var response = client.Execute(request);

回答3:

The example below - how to upload an image file to Amazon S3 bucket using pre-signed URL. RestSharp library.

public void UploadToS3PresignedUrl(string s3presignedUrl, byte[] imageByte)
{
    var request = new RestRequest(s3presignedUrl, Method.PUT);

    request.AddHeader("Content-Type", "image/jpeg");
    request.AddParameter("application/octet-stream", imageByte, ParameterType.RequestBody);

    var client = new RestClient();
    client.Execute(request);
}

来源：https://stackoverflow.com/questions/32876606/restsharp-addfile-using-stream

标签

upload

streaming

restsharp