sandbox / Mbed OS http-example

HTTP and HTTPS example application for Mbed OS 5

Dependencies:   mbed-http

This application demonstrates how to make HTTP and HTTPS requests and parse the response from Mbed OS 5.

It consists of six example applications, which you can select in source/select-demo.h:

Response parsing is done through nodejs/http-parser.

Note: HTTPS requests do not work on targets with less than 128K of RAM due to the size of the TLS handshake. For more background see mbed-http.

To build

  1. If you're using WiFi, specify the credentials in mbed_app.json.
  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.

Defining the network interface

This application uses the on-board network interface for your board. If you use an external network interface (f.e. a WiFi module) you need to add the driver to this project. Then, open network-helper.h and specify which network driver to use.

More information is in the Mbed OS documentation under IP Networking.

Entropy (or lack thereof)

On all platforms that do not have the TRNG feature, 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.

Flash size

Default flash size for HTTPS is very large, as the application is loading the default Mbed TLS configuration. To use a more optimized version, you can disable unused cypher suites and other Mbed TLS features with a custom configuration file. Create a new configuration file, then add in mbed_app.json:

"MBEDTLS_CONFIG_FILE=\"mbedtls_config.h\""

to the macros array.

Running tests

You can run the integration tests from this project via Mbed CLI.

  1. In select-demo.h set the DEMO macro to DEMO_TESTS.
  2. Set your WiFi credentials in mbed_app.json.
  3. Then run the tests via: 

$ mbed test -v -n mbed-http-tests-tests-*

Tested on

  • K64F with Ethernet.
  • NUCLEO_F411RE with ESP8266 (not working on Mbed OS 5.12+)
  • ODIN-W2 with WiFi.
  • K64F with Atmel 6LoWPAN shield.
  • DISCO-L475VG-IOT01A with WiFi (requires the wifi-ism43362 driver).

source/main-http-socket-reuse.cpp

Committer:
Jan Jongboom
Date:
2019-01-04
Revision:
35:4b847971db1b
Parent:
31:66704f6f17c5

File content as of revision 35:4b847971db1b:

#include "select-demo.h"

#if DEMO == DEMO_HTTP_SOCKET_REUSE

#include "mbed.h"
#include "network-helper.h"
#include "http_request.h"

void dump_response(HttpResponse* res) {
    printf("Status: %d - %s\n", res->get_status_code(), res->get_status_message().c_str());

    printf("Headers:\n");
    for (size_t ix = 0; ix < res->get_headers_length(); ix++) {
        printf("\t%s: %s\n", res->get_headers_fields()[ix]->c_str(), res->get_headers_values()[ix]->c_str());
    }
    printf("\nBody (%d bytes):\n\n%s\n", res->get_body_length(), res->get_body_as_string().c_str());
}

int main() {
    NetworkInterface* network = connect_to_default_network_interface();
    if (!network) {
        printf("Cannot connect to the network, see serial output\n");
        return 1;
    }

    // Create a TCP socket
    printf("\n----- Setting up TCP connection -----\n");

    TCPSocket* socket = new TCPSocket();
    nsapi_error_t open_result = socket->open(network);
    if (open_result != 0) {
        printf("Opening TCPSocket failed... %d\n", open_result);
        return 1;
    }

    nsapi_error_t connect_result = socket->connect("httpbin.org", 80);
    if (connect_result != 0) {
        printf("Connecting over TCPSocket failed... %d\n", connect_result);
        return 1;
    }

    printf("Connected over TCP to httpbin.org:80\n");

    // Do a GET request to httpbin.org
    {
        HttpRequest* get_req = new HttpRequest(socket, HTTP_GET, "http://httpbin.org/status/418");

        // By default the body is automatically parsed and stored in a string, this is memory heavy.
        // To receive chunked response, pass in a callback as third parameter to 'send'.
        HttpResponse* get_res = get_req->send();
        if (!get_res) {
            printf("HttpRequest failed (error code %d)\n", get_req->get_error());
            return 1;
        }

        printf("\n----- HTTP GET response -----\n");
        dump_response(get_res);

        delete get_req;
    }

    // POST request to httpbin.org
    {
        HttpRequest* post_req = new HttpRequest(socket, HTTP_POST, "http://httpbin.org/post");
        post_req->set_header("Content-Type", "application/json");

        const char body[] = "{\"hello\":\"world\"}";

        HttpResponse* post_res = post_req->send(body, strlen(body));
        if (!post_res) {
            printf("HttpRequest failed (error code %d)\n", post_req->get_error());
            return 1;
        }

        printf("\n----- HTTP POST response -----\n");
        dump_response(post_res);

        delete post_req;
    }

    socket->close();
    delete socket;

    wait(osWaitForever);
}

#endif