Ken Krugler wrote:
A few answers in-line below.
Disclaimer: I've ported some HttpClient 3.1 code to 4.0, but I haven't
made heavy use of the full 4.0 functionality.
I am new to HTTPComponents Client but have been using HttpClient 3.1 very
extensively... So I am facing some migration work.
1. How do I measure the time it took to get a response in a multithreaded
scenario with a limited size of max total connections?
In 3.1 I had to hack this into a custom ProtocolSocketFactory. When the
socket is created I am rembering the time in a thread local scope.
>>
Is that still the way to go?
Michael,
I would recommend using custom protocol interceptors to collect
performance related metrics. Use a request interceptor to store the
start time in the HTTP context, and a response interceptor to store the
finish time. For details see:
http://hc.apache.org/httpcomponents-client/tutorial/html/fundamentals.html#d4e290
2. I want to set a different user agent per request
In 3.1 I could set HostParams when executing the method. How does it work
now?
I believe you'd want to implement a RequestUserAgent class that sets up
the user agent that you want.
Seems like you might be able to do the same thing via using an
HttpContext, but Oleg would know best.
One could also use the 'http.useragent' parameter:
http://hc.apache.org/httpcomponents-client/tutorial/html/fundamentals.html#d4e337
3. Setting a proxy per request
httpClient.execute(proxyHost, httpget, responseHandler);
Correct?
Use 'http.route.default-proxy' parameter.
http://hc.apache.org/httpcomponents-client/tutorial/html/ch02.html#d4e465
http://hc.apache.org/httpcomponents-client/tutorial/html/ch02.html#d4e540
4. Disabling redirects
params.setBooleanParameter(ClientPNames.HANDLE_REDIRECTS, false);
Correct?
Yes.
5. Enabling my own retry handler (which I just need because of verbose
logging)
((DefaultHttpClient) this.httpClient).setHttpRequestRetryHandler(XXX);
Correct?
Yes.
6. When using the ThreadSafeClientConnManager how can I monitor the
number
of threads used or threads waiting?
Well, you can call getConnectionsInPool() to get the number of in-use
connections, though I think that would include connections that are no
longer active but haven't been released back.
"Threads waiting" would (I assume) mean the number of HTTP requests
you've made where no free connection is available, and thus the request
is hung in ClientConnectionRequest.getConnection() until it gets a
connection to use, or it times out.
There must be some way to find this out, but it's not obvious from the
APIs.
I guess the ThreadSafeClientConnManager is the replacement of the
MultiThreadedHttpConnectionManager?
Yes, I believe so. Or at least that's what I've changed my 3.1 code to
use with 4.0.
-- Ken
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