HTTP() from std.net.curl hidden state

[Ilya Korobitsyn via Digitalmars-d-learn]

Hello!

I am using HTTP structure to perform calls to a simple REST API.
Like this:

class API
{
      HTTP http;
      this() { http = HTTP(); }
      void call() {
           http.url = "some url";
           http.method = POST;
           http.setPostData("data", "type");
           http.perform();
      }
}

My issue is that I have to reinitialize http with HTTP() every 
call(), otherwise some state keeps on adding. For example, 
headers Content-Type keep on multiplying, and after setting 
method to DELETE it can not be changed to POST again (request 
still sends as delete).

Reinitializing http seems fine, however I suspect that something 
is lost (DNS cache, from example). Is there any workaround?

Thank you.

Example (without reinitialization):
3 subsequent requests with verbose curl, >> lines are what is 
desired, << received, rest is curl debug output.

>> POST http://localhost:9515/session
>> {"desiredCapabilities":{},"requiredCapabilities":{}}
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 9515 (#0)
> POST /session HTTP/1.1
User-Agent: Phobos-std.net.curl/2.067 (libcurl/7.35.0)
Host: localhost:9515
Accept: */*
Content-Type: application/json;charset=UTF-8
Content-Length: 52
* upload completely sent off: 52 out of 52 bytes
< HTTP/1.1 200 OK
< Content-Length:550
< Content-Type:application/json; charset=utf-8
< Connection:close
<
* Closing connection 0
<< 200 
{"sessionId":"d833e91674e2d14d2a81133821ab76fd","status":0,"value":{"acceptSslCerts":true,"applicationCacheEnabled":false,"browserConnectionEnabled":false,"browserName":"chrome","chrome":{"userDataDir":"/tmp/.com.google.Chrome.AlM0Ze"},"cssSelectorsEnabled":true,"databaseEnabled":false,"handlesAlerts":true,"javascriptEnabled":true,"locationContextEnabled":true,"mobileEmulationEnabled":false,"nativeEvents":true,"platform":"Linux","rotatable":false,"takesHeapSnapshot":true,"takesScreenshot":true,"version":"41.0.2272.76","webStorageEnabled":true}}


>> DELETE 
>> http://localhost:9515/session/d833e91674e2d14d2a81133821ab76fd
* Hostname was found in DNS cache
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 9515 (#1)
> DELETE /session/d833e91674e2d14d2a81133821ab76fd HTTP/1.1
User-Agent: Phobos-std.net.curl/2.067 (libcurl/7.35.0)
Host: localhost:9515
Accept: */*
Content-Type: application/json;charset=UTF-8
Content-Type: text/plain
Content-Length: 0
< HTTP/1.1 200 OK
< Content-Length:72
< Content-Type:application/json; charset=utf-8
< Connection:close
<
* Closing connection 1
<< 200 
{"sessionId":"d833e91674e2d14d2a81133821ab76fd","status":0,"value":null}


>> POST http://localhost:9515/session
>> {"desiredCapabilities":{},"requiredCapabilities":{}}
* Hostname was found in DNS cache
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 9515 (#2)
> DELETE /session HTTP/1.1
User-Agent: Phobos-std.net.curl/2.067 (libcurl/7.35.0)
Host: localhost:9515
Accept: */*
Content-Type: application/json;charset=UTF-8
Content-Type: text/plain
Content-Type: application/json;charset=UTF-8
Content-Length: 52
* upload completely sent off: 52 out of 52 bytes
< HTTP/1.1 404 Not Found
< Content-Length:24
< Content-Type:text/plain
< Connection:close
<
* Closing connection 2
<< 404 unknown command: session