Re: [lwip-users] http post using lwip?

Hi all,

I think i have "something" up for review. The thing is, there are a couple of ways I can approach this. I think the most important one is, whether to have one function for httpc_create_request_string, or make dedicated ones for http_get, http_post, etc. I think it's a matter of taste.

This is what I have now:

static int
httpc_create_request_string(const httpc_connection_t *settings, const char* server_name, int server_port, const char* uri,
                            const httpc_request_info_t* request_info, int use_host, char *buffer, size_t buffer_size)
{
  LWIP_ASSERT("request_info != NULL", request_info != NULL);

  if (request_info->request_type == HTTPC_GET) {
    if (settings->use_proxy) {
      LWIP_ASSERT("server_name != NULL", server_name != NULL);
      if (server_port != HTTP_DEFAULT_PORT) {
        return snprintf(buffer, buffer_size, HTTPC_REQ_11_PROXY_PORT_FORMAT(server_name, server_port, uri, server_name));
      } else {
        return snprintf(buffer, buffer_size, HTTPC_REQ_11_PROXY_FORMAT(server_name, uri, server_name));
      }
    } else if (use_host) {
      LWIP_ASSERT("server_name != NULL", server_name != NULL);
      return snprintf(buffer, buffer_size, HTTPC_REQ_11_HOST_FORMAT(uri, server_name));
    } else {
      return snprintf(buffer, buffer_size, HTTPC_REQ_11_FORMAT(uri));
    }
  } else if (request_info->request_type == HTTPC_POST) {
    if (settings->use_proxy) {
      LWIP_ASSERT("server_name != NULL", server_name != NULL);
      if (server_port != HTTP_DEFAULT_PORT) {
        return snprintf(buffer, buffer_size, HTTPC_POST_REQ_11_PROXY_PORT_FORMAT(
          server_name, 
          server_port, 
          uri, 
          server_name,
          get_application_type(request_info->application_type),
          strlen(request_info->payload),
          request_info->payload));
      } else {
        return snprintf(buffer, buffer_size, HTTPC_POST_REQ_11_PROXY_FORMAT(
          server_name, 
          uri, 
          server_name,
          get_application_type(request_info->application_type),
          strlen(request_info->payload),
          request_info->payload));
      }
    } else if (use_host) {
      LWIP_ASSERT("server_name != NULL", server_name != NULL);
      return snprintf(buffer, buffer_size, HTTPC_POST_REQ_11_HOST_FORMAT(
        uri, 
        server_name,
        get_application_type(request_info->application_type),
        strlen(request_info->payload),
        request_info->payload));
    } else {
      return snprintf(buffer, buffer_size, HTTPC_POST_REQ_11_FORMAT(
        uri,
        get_application_type(request_info->application_type),
        strlen(request_info->payload),
        request_info->payload));
    }
  } else {
    LWIP_ASSERT("request_type not supported", 0);
  }
}

The http_client.h is changed as follows:

// Intended left the existing prototypes of httpc_get UNCHANGED
err_t httpc_get_file(const ip_addr_t* server_addr, u16_t port, const char* uri, const httpc_connection_t *settings,
                     altcp_recv_fn recv_fn, void* callback_arg, httpc_state_t **connection);
err_t httpc_get_file_dns(const char* server_name, u16_t port, const char* uri, const httpc_connection_t *settings,
                     altcp_recv_fn recv_fn, void* callback_arg, httpc_state_t **connection);

// Added httpc_post prototypes (and can add put/delete as well)

err_t httpc_post_file(const ip_addr_t* server_addr, u16_t port, const char* uri, httpc_request_info_t* post_info, 
                      const httpc_connection_t *settings, altcp_recv_fn recv_fn, void* callback_arg, httpc_state_t **connection);
err_t httpc_post_file_dns(const char* server_name, u16_t port, const char* uri, httpc_request_info_t* post_info, 
                          const httpc_connection_t *settings, altcp_recv_fn recv_fn, void* callback_arg, httpc_state_t **connection);

It works, I just tested it on my imx board.

Some discussion points:

- I created an enum for the application type of the post message. For now, I only support json (=application/json) (since that's what I need ;-)). Should I add more? I don't know what the most interesting ones are to add.

- Are the application types always supported by POST/PUT? Like application/json will be OK for both POST and PUT. Are there others that are only allowed for POST / PUT?

- The "to be sent data" is incorporated in the header. This will potentially make the header pretty large. Is that OK? Or should there be a different mechanism in place to make lwip send larger files to the server in chunks? Or will lwip deal with that in the lwip core?

- Or should I just make a pull request and let you guys nuke it with comments? :)

Best regards, Bas

Op za 2 jul. 2022 om 08:47 schreef Bas Prins <bas.prins3@gmail.com>:

Hi!
Thx a lot. Was't that certain I just needed the extra confirmation that it was as simple as extending the client. Will give this a go after my holidays. I will figure out how to make a pull request after.

Thanks!

Op za 2 jul. 2022 00:34 schreef Grant Edwards <grant.b.edwards@gmail.com>:
On 2022-07-01, Simon Goldschmidt <goldsimon@gmx.de> wrote:

>>I'd really appreciate some feedback on this. Would it make sense to
>>extend the http_client.c in such a way so that I can choose whether
>>to create HTTP_GET or HTTP_POST requests?
>
> Yes.
>

>>err_t httpc_get_file_dns(const char* server_name, u16_t port, const
>>char* uri, const httpc_connection_t *settings, altcp_recv_fn
>>recv_fn, void* callback_arg, httpc_state_t **connection);
>>
>>For example add parameters to that signature to specify the request
>>type? GET/POST + optional post data ?
>
> No, that function is called GET. Add a function called POST and add
> the new code there.

Might as well add PUT at the same time?

Maybe DELETE also?

--
Grant

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From:	Bas Prins
Subject:	Re: [lwip-users] http post using lwip?
Date:	Mon, 4 Jul 2022 10:24:42 +0200