Demonstration program with support for the WNC M14A2A Cellular LTE Data Module added. An additional demonstration program was also added that shows a few other features (for chunked responses).

Dependencies:   easy-connect mbed-http

mbed-os-example-http(s) using WNC 14A2A Data Module

This application builds on the application provided by ARM (see https://developer.mbed.org/teams/sandbox/code/mbed-http/). It demonstrates how to make HTTP and HTTPS requests and parse the response from mbed OS 5.

There are a total of five demo's, which can be selected by modifying source/select-demo.h.

1. HTTP demo (DEMO_HTTP):

2. HTTPS demo (DEMO_HTTPS):

3. HTTP demo with socket re-use (DEMO_HTTP_SOCKET_REUSE).

  • Similar to the HTTP demo but reuses the socket for all interactions

4. HTTPS demo with socket re-use (DEMO_HTTPS_SOCKET_REUSE).

  • Similar to the HTTPS demo above

5. HTTP & HTTPS demo with socket re-use and chunked call-backs (DEMO_HTTPx)

Response parsing is done through [nodejs/http-parser](https://github.com/nodejs/http-parser).

To build

1. Open ``mbed_app.json`` and change the `network-interface` option to your connectivity method ([more info](https://github.com/ARMmbed/easy-connect)). 2. Build the project in the online compiler or using mbed CLI. 3. Flash the project to your development board. 4. Attach a serial monitor to your board to see the debug messages.

Entropy (or lack thereof)

On all platforms except the FRDM-K64F and FRDM-K22F the application is compiled without TLS entropy sources. This means that your code is inherently unsafe and should not be deployed to any production systems. To enable entropy, remove the `MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES` and `MBEDTLS_TEST_NULL_ENTROPY` macros from mbed_app.json.

Tested on

  • K64F with Ethernet.
  • NUCLEO_F411RE with ESP8266.
  • AT&T Cellular IoT Starter Kit with WNC M14A2A Cellular Data Module

The WNCInterface class currently supports the following version(s):

  • MPSS: M14A2A_v11.50.164451 APSS: M14A2A_v11.53.164451

License

This library is released under the Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License and may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

source/mbed-http/http_request.h

Committer:
Jan Jongboom
Date:
2017-02-16
Revision:
1:3bff14db67c7

File content as of revision 1:3bff14db67c7:

#ifndef _HTTP_REQUEST_
#define _HTTP_REQUEST_

#include <string>
#include <vector>
#include <map>
#include "http_parser.h"
#include "http_response.h"
#include "http_request_builder.h"
#include "http_response_parser.h"
#include "http_parsed_url.h"

/**
 * @todo:
 *      - Userinfo parameter is not handled
 *      - Allow socket re-use
 */


/**
 * \brief HttpRequest implements the logic for interacting with HTTPS servers.
 */
class HttpRequest {
public:
    /**
     * HttpRequest Constructor
     *
     * @param[in] aNetwork The network interface
     * @param[in] aMethod HTTP method to use
     * @param[in] url URL to the resource
     * @param[in] aBodyCallback Callback on which to retrieve chunks of the response body.
                                If not set, the complete body will be allocated on the HttpResponse object,
                                which might use lots of memory.
    */
    HttpRequest(NetworkInterface* aNetwork, http_method aMethod, const char* url, Callback<void(const char *at, size_t length)> aBodyCallback = 0)
        : network(aNetwork), method(aMethod), body_callback(aBodyCallback)
    {
        error = 0;
        response = NULL;

        parsed_url = new ParsedUrl(url);
        request_builder = new HttpRequestBuilder(method, parsed_url);
    }

    /**
     * HttpRequest Constructor
     */
    ~HttpRequest() {
        // should response be owned by us? Or should user free it?
        // maybe implement copy constructor on response...
        if (response) {
            delete response;
        }

        if (parsed_url) {
            delete parsed_url;
        }

        if (request_builder) {
            delete request_builder;
        }
    }

    /**
     * Execute the request and receive the response.
     */
    HttpResponse* send(const void* body = NULL, nsapi_size_t body_size = 0) {
        if (response != NULL) {
            // already executed this response
            error = -2100; // @todo, make a lookup table with errors
            return NULL;
        }

        error = 0;

        TCPSocket socket;

        nsapi_error_t open_result = socket.open(network);
        if (open_result != 0) {
            error = open_result;
            return NULL;
        }

        nsapi_error_t connection_result = socket.connect(parsed_url->host(), parsed_url->port());
        if (connection_result != 0) {
            error = connection_result;
            return NULL;
        }

        char* request = request_builder->build(body, body_size);
        size_t request_size = strlen(request);

        nsapi_size_or_error_t send_result = socket.send(request, request_size);

        free(request);

        if (send_result != request_size) {
            error = send_result;
            return NULL;
        }

        // Create a response object
        response = new HttpResponse();
        // And a response parser
        HttpResponseParser parser(response, body_callback);

        // Set up a receive buffer (on the heap)
        uint8_t* recv_buffer = (uint8_t*)malloc(HTTP_RECEIVE_BUFFER_SIZE);

        // TCPSocket::recv is called until we don't have any data anymore
        nsapi_size_or_error_t recv_ret;
        while ((recv_ret = socket.recv(recv_buffer, HTTP_RECEIVE_BUFFER_SIZE)) > 0) {
            // Pass the chunk into the http_parser
            size_t nparsed = parser.execute((const char*)recv_buffer, recv_ret);
            if (nparsed != recv_ret) {
                // printf("Parsing failed... parsed %d bytes, received %d bytes\n", nparsed, recv_ret);
                error = -2101;
                free(recv_buffer);
                return NULL;
            }
            // No more chunks? break out of this loop
            if (recv_ret < HTTP_RECEIVE_BUFFER_SIZE) {
                break;
            }
        }
        // error?
        if (recv_ret < 0) {
            error = recv_ret;
            free(recv_buffer);
            return NULL;
        }

        // When done, call parser.finish()
        parser.finish();

        // Free the receive buffer
        free(recv_buffer);

        // Close the socket
        socket.close();

        return response;
    }

    /**
     * Set a header for the request.
     *
     * The 'Host' and 'Content-Length' headers are set automatically.
     * Setting the same header twice will overwrite the previous entry.
     *
     * @param[in] key Header key
     * @param[in] value Header value
     */
    void set_header(string key, string value) {
        request_builder->set_header(key, value);
    }

    /**
     * Get the error code.
     *
     * When send() fails, this error is set.
     */
    nsapi_error_t get_error() {
        return error;
    }

private:
    NetworkInterface* network;
    http_method method;
    Callback<void(const char *at, size_t length)> body_callback;

    ParsedUrl* parsed_url;

    HttpRequestBuilder* request_builder;
    HttpResponse* response;

    nsapi_error_t error;
};

#endif // _HTTP_REQUEST_