Content length is 0 in http post response in resin 3.0 - java

I have a client who is posting some data to our server with http POST method. Our server is resin 3.0 with java. When I send response whether data is saved or not the the content length of the response is not set. client is using curl library(php wrapper over it) and they are receiving content length as 0. When I try to submit a form through a browser to our server on the same url it works and response is shown.
I tried using Apache HttpClient to submit data through postmethod and I received content length as -1 but i did get the full response. I'm not able to understand where is the problem. Also I did some google and found that resin do some chunked encoding while sending the response. But i guess it does this also for GET method. But for GET method my client is getting the content length and is able to get the response as well. Need help with this.

"Content-Length" is a header in the response, which warns the client on how big the response will be. It is not the actual length of the stream.
You can set it's value with response.setContentLength(...); in your Servlet.

Related

How to read response data in an Undertow HttpServerExchange object?

I have implemented a reverse proxy with Undertow server.
I want to edit the absolute URLs in the response from target host before sending back to client.
I've used exchange.addResponseCommitListener(httpHandler) so that exchange object contains response from the proxied server and the response hasn't been sent to the client yet.
In httpHandler, I'm able to see the exact length of the proxied response with exchange.getResponseContentLength() but unable to find any function that reads the response data.
I've checked the implementation of exchange.getResponseContentLength() but its only giving the value from one of response headers Content-Length.
Can anyone please help me how to retrieve the response data that has been proxied. Thanks

Jersey client.setChunkedEncodingSize(null) not working

I am writing one client to measure Jersey, REST based web service performance. I have written some code to measure response time and to measure number of bytes sent from the server but response.getLength() method always returning -1.
In many QA forum I read that setting client.setChunkedEncodingSize(null) will work but even after setting this, I am getting -1.
From server side, I am sending response of type XML or JSON or protobuf depending upon parameters sent by client. For all of these response types, I am getting response length as -1.
My actual request looks like below:
WebResource webResourceQuery = client.resource(requestUrl);
ClientResponse response = webResourceQuery.header("Authorization", header)
.accept(MediaType.APPLICATION_JSON)
.get(ClientResponse.class);
From server side, I am not setting content-length explicitly. Can anyone please help me in getting content-length on client side?
Whole purpose of this experiment is to measure which response type is more efficient in terms of response time and amount of data sent/received.
I ran in to the same problem: client.setChunkedEncodingSize(null); does not work.
This worked for me to actually disable chunked encoding:
client.getProperties().put(ApacheHttpClient4Config.PROPERTY_ENABLE_BUFFERING, true);

Java - send HTTP POST request without downloading all the content

Is it possible to send HTTP POST request to a webserver and retrieve just headers of response or read just few bytes of the body, so the rest won't be downloaded at all (so it won't consume traffic)? If yes, how?
I know that there is a HEAD method for this, but I need to achieve it by POST method .. well, I am not sure if I need the POST method, I just need to post the data. Maybe if the webserver isn't secured well enough (it doesn't check what method it's used - it's just directly access the post data), is it possible to send "post data" by HEAD request?
There is no built-in HTTP mechanism for this, and HTTP HEAD requests do not allow content in the body. If however you are the one writing the server code then anything is possible.
If this is the case, I would suggest a URL parameter that triggers this behavior. For example:
POST /myURL - This would return the whole response
POST /myURL?body=minimal - Returns the reduced size response that you are looking for.
And you would have to code your server method to construct and return the appropriate response based on the URL parameter.

Getting "411 Length Required" after a PUT request from HTTP Client

I am working on a Java program that implements an HTTP Client.
I test it sending requests to a server. GET, POST and DELETE requests work ok.
For example after a POST request I get an output
Data extracted:
{"status":{"message":"ok"}}
and the database reflects the changes made.
After a PUT request, however I get the following html markup of a webpage indicating an error.
Data extracted:
<html>
<head><title>411 Length Required</title></head>
<body bgcolor="white">
<center><h1>411 Length Required</h1></center>
<hr><center>nginx/1.2.6</center>
</body>
</html>
and accordingly no changes in the database.
I found that this can have something to do with the Content-Length header, but I'm not sure.
After trying to add this header my program waits for a minute and then throws an exception informing that it couldn't handle the server response.
I can also provide any code or stack trace if needed.
Yes, the issue related to Content-Length. HTTP Error 411 means
The server refuses to accept the request without a defined Content- Length. The client MAY repeat the request if it adds a valid Content-Length header field containing the length of the message-body in the request message.
So when you send an empty RequestBody in POST/PUT Method then you also need to send Content-Length:0. So add this header in your request. I don't think this header will cause a problem of you added into Request Object.

Setting content length of an HTTP POST request

I am trying to make a Http POST request using apache HTTP client. I am trying to copy contents of an HTTP POST request (received at my application) to another HTTP POST request (initiated from my application to another URL). Code is shown below:
httpPost = new HttpPost(inputURL);
// copy headers
for (Enumeration<String> e = request.getHeaderNames(); e.hasMoreElements();) {
String headerName = e.nextElement().toString();
httpPost.setHeader(headerName, request.getHeader(headerName));
}
BufferedInputStream clientToProxyBuf = new BufferedInputStream(request.getInputStream());
BasicHttpEntity basicHttpEntity = new BasicHttpEntity();
basicHttpEntity.setContent(clientToProxyBuf);
basicHttpEntity.setContentLength(clientToProxyBuf.available());
httpPost.setEntity(basicHttpEntity);
HttpResponse responseFromWeb = httpclient.execute(httpPost);
Basically, I am trying to implement a proxy application which will get a url as parameter, froward the request to the URL and then serve pages etc in custom look and feel.
Here request is HttpServletRequest. I am facing problem in setting content length. Through debugging I found out that clientToProxyBuf.available() is not giving me correct length of input stream and I am getting Http error 400 IE and Error 354 (net::ERR_CONTENT_LENGTH_MISMATCH): The server unexpectedly closed the connection in chrome.
Am I doing it wrong? Is there any other way to achieve it?
The available() function doesn't provide the actual length of the content of the stream, rather
Returns the number of bytes that can be read from this input stream without blocking. (From javadoc)
I would suggest you to first read the whole content from the stream, and then set that to the content, rather than passing the stream object. That way, you will also have the actual length of the content.
It was rather simple and very obvious. I just needed to get content length from header as:
basicHttpEntity.setContentLength(Integer.parseInt(request.getHeader("Content-Length")));

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