C#

REST Read Response with Stream API

See more REST Examples

Demonstrates how to make a REST call that returns a binary body, and to receive the body through a stream API. C#

bool success = false;

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Rest rest = new Chilkat.Rest();

// Connect to the Amazon AWS REST server.
bool bTls = true;
int port = 443;
bool bAutoReconnect = true;
success = rest.Connect("s3.amazonaws.com",port,bTls,bAutoReconnect);

// ----------------------------------------------------------------------------
// Important: For buckets created in regions outside us-east-1,
// there are three important changes that need to be made.
// See Working with S3 Buckets in Non-us-east-1 Regions for the details.
// ----------------------------------------------------------------------------

// Provide AWS credentials for the REST call.
Chilkat.AuthAws authAws = new Chilkat.AuthAws();
authAws.AccessKey = "AWS_ACCESS_KEY";
authAws.SecretKey = "AWS_SECRET_KEY";
authAws.ServiceName = "s3";
success = rest.SetAuthAws(authAws);

// Set the bucket name via the HOST header.
// In this case, the bucket name is "chilkat100".
rest.Host = "chilkat100.s3.amazonaws.com";

// Send the request to download the JPG.
success = rest.SendReqNoBody("GET","/starfish.jpg");
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// Read the response header.
int responseStatusCode = rest.ReadResponseHeader();
if (responseStatusCode < 0) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

Debug.WriteLine("Response status code = " + Convert.ToString(responseStatusCode));

// We expect a 200 response status if the JPG data is coming.
// Otherwise, we'll get a string response body with an error message(or no response body).
if (responseStatusCode != 200) {
    string errResponse = rest.ReadRespBodyString();
    if (rest.LastMethodSuccess != true) {
        Debug.WriteLine(rest.LastErrorText);
    }
    else {
        Debug.WriteLine(errResponse);
    }

    return;
}

Chilkat.Stream bodyStream = new Chilkat.Stream();
// Set a 10 second read timeout for the stream. 
// (Give up if no data arrives within 10 seconds after calling a read method.)
bodyStream.ReadTimeoutMs = 10000;

// Create a background thread task to read the response body (which feeds
// it to the bodyStream object.)
Chilkat.Task readResponseBodyTask = rest.ReadRespBodyStreamAsync(bodyStream,true);

// Start the task. 
success = readResponseBodyTask.Run();

// The application can now read the bodyStream...
while ((bodyStream.EndOfStream != true)) {

    // Read the next chunk of bytes (whatever is immediately available,
    // or wait for more data (up to 10 seconds because we set the stream's ReadTimeoutMs property)
    byte[] nextChunk = bodyStream.ReadBytes();
    if (bodyStream.LastMethodSuccess != true) {
        Debug.WriteLine("Failed to receive more response data.");
        // Make sure the background task is aborted/cancelled.
        success = readResponseBodyTask.Cancel();

        return;
    }

    // OK.. the app has the next chunk of the body, and may do whatever it wishes with it...
}

Debug.WriteLine("Successfully received the entire response body.");