C++ cpprestsdk POST question

I should add that the code that works was adapted from http://www.drdobbs.com/windows/using-the-microsoft-c-rest-sdk/240164544?pgno=2 with many thanks to that author.

I have never used this SDK, but when it comes to doing POST requests, you typically should include the "Content-Length" and "Content-Type" headers.

The code you posted uses an instance of http_client to send the request, but I don't see a way to augment the headers.  However, if you look at the http_client class reference, you will notice that the first response() method listed accepts an instance of http_request.  So, try creating an instance of http_request an add the headers I mentioned above.  So, try:

pplx::task<void> HTTPPostAsync(){
	http_client client("http://localhost/path/to/file.php");

	http_request request(methods::POST);
	request.headers().add("Content-Type", "application/x-www-form-urlencoded");
	request.headers().add("Content-Length", "21");//length of the submitted data/payload (in bytes)
	// request.headers().add("Host", "ericzwar.com");
	request.headers().add("X-Requested-With", "Casablanca");
	request.set_body("user=john&password=hi");// 21 bytes long

	return client.request(request).then([](http_response response){
		// process response here
	});
}

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Hi Hielo,  thank you for your response but I get two errors:

no instance of function template "web::http::http_headers::add" matches the argument list      
argument types are: (const char [13], const char [34])
object type is: web::http::http_headers

This error shows if I leave the () in.  (It is in lines 22 and 23 in my source but lines 5 and 6 in your example above)

If I leave the () out then I get:
"left of add must have a class/struct/union" (lines 5 and 6 in your example)  - lines 22 and 23 in my source.

I have Googled on these errors but can't seem to find exactly what is required.

Looking forward to your advice and thank you in anticipation.

Note: my environment is Windows 7 with Visual Studio 2015 Community if that helps.

I found a headers test page where the values are U("...") instead of just "...", so try:

	request.headers().add( U("Content-Type"), U("application/x-www-form-urlencoded") );
	request.headers().add( U("Content-Length"), U("21") );//length of the submitted data/payload (in bytes)

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Also, I looked at the http_headers class reference and I see that it contains the following methods:

• set_content_type(utility::string_t type)
• set_content_length(utility::size64_t length)

So, if the suggestion above does not work, try calling those methods.

Line 320 shows you how to call set_content_length() (and its argument type is on line 319).

lines 124 & 125 show you how to call set_content_type().  In case you are wondering where those arguments come from, look at the #ifdef _MIME_TYPES section of http_constants.dat.  So, you will need:

request.headers().set_content_type(web::http::details::mime_types::application_x_www_form_urlencoded);

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>> Note: my environment is Windows 7 with Visual Studio 2015 Community if that helps.
Not at all.  I've never used Visual Studio nor Casablanca :)

Hi Hielo,

BEAUTIFUL!!  Your first suggestion worked perfectly - THANK YOU SOOOOO much!

After I clean my working code up I will post it in full in case it is of use to others but that won't get done for a few hours yet.

I also had to add the include "cpprest/http_headers.h"

Cheers, Eric.

Have posted the 'cleaned-up' code in case it is of interest to someone else.  Did not need the header I mentioned above nor the 'content length' statement.

Again, Hielo's help has been much appreciated.
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