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.cpp@17:97b1dd566b07, 2017-09-04 (annotated)

Committer:
Jan Jongboom
Date:
Mon Sep 04 17:01:11 2017 +0100
Revision:
17:97b1dd566b07
Parent:
15:65a49b573ba5
Child:
20:d851bc648f9e
Enable entropy sources for ODIN-W2; add note on memory usage

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Jan Jongboom 0:85fdc69bc10c 1 #include "select-demo.h"
Jan Jongboom 0:85fdc69bc10c 2
Jan Jongboom 0:85fdc69bc10c 3 #if DEMO == DEMO_HTTP
Jan Jongboom 0:85fdc69bc10c 4
Jan Jongboom 0:85fdc69bc10c 5 #include "mbed.h"
Jan Jongboom 0:85fdc69bc10c 6 #include "easy-connect.h"
Jan Jongboom 0:85fdc69bc10c 7 #include "http_request.h"
Jan Jongboom 17:97b1dd566b07 8 #include "mbed_stats.h"
Jan Jongboom 0:85fdc69bc10c 9
Jan Jongboom 0:85fdc69bc10c 10 Serial pc(USBTX, USBRX);
Jan Jongboom 0:85fdc69bc10c 11
Jan Jongboom 0:85fdc69bc10c 12 void dump_response(HttpResponse* res) {
Jan Jongboom 0:85fdc69bc10c 13 printf("Status: %d - %s\n", res->get_status_code(), res->get_status_message().c_str());
Jan Jongboom 0:85fdc69bc10c 14
Jan Jongboom 0:85fdc69bc10c 15 printf("Headers:\n");
Jan Jongboom 0:85fdc69bc10c 16 for (size_t ix = 0; ix < res->get_headers_length(); ix++) {
Jan Jongboom 7:5d32909f77de 17 printf("\t%s: %s\n", res->get_headers_fields()[ix]->c_str(), res->get_headers_values()[ix]->c_str());
Jan Jongboom 0:85fdc69bc10c 18 }
Jan Jongboom 5:42f713b19337 19 printf("\nBody (%d bytes):\n\n%s\n", res->get_body_length(), res->get_body_as_string().c_str());
Jan Jongboom 0:85fdc69bc10c 20 }
Jan Jongboom 0:85fdc69bc10c 21
Jan Jongboom 0:85fdc69bc10c 22 int main() {
Jan Jongboom 0:85fdc69bc10c 23 pc.baud(115200);
Jan Jongboom 17:97b1dd566b07 24
Jan Jongboom 17:97b1dd566b07 25 mbed_stats_heap_t heap_stats;
Jan Jongboom 17:97b1dd566b07 26
Jan Jongboom 17:97b1dd566b07 27 mbed_stats_heap_get(&heap_stats);
Jan Jongboom 17:97b1dd566b07 28 printf("[1] Heap: %lu / %lu, max=%lu\n", heap_stats.current_size, heap_stats.reserved_size, heap_stats.max_size);
Jan Jongboom 17:97b1dd566b07 29
Jan Jongboom 0:85fdc69bc10c 30 // Connect to the network (see mbed_app.json for the connectivity method used)
Jan Jongboom 15:65a49b573ba5 31 NetworkInterface* network = easy_connect(true);
Jan Jongboom 0:85fdc69bc10c 32 if (!network) {
Jan Jongboom 0:85fdc69bc10c 33 printf("Cannot connect to the network, see serial output");
Jan Jongboom 0:85fdc69bc10c 34 return 1;
Jan Jongboom 0:85fdc69bc10c 35 }
Jan Jongboom 0:85fdc69bc10c 36
Jan Jongboom 17:97b1dd566b07 37 mbed_stats_heap_get(&heap_stats);
Jan Jongboom 17:97b1dd566b07 38 printf("[2] Heap: %lu / %lu, max=%lu\n", heap_stats.current_size, heap_stats.reserved_size, heap_stats.max_size);
Jan Jongboom 17:97b1dd566b07 39
Jan Jongboom 0:85fdc69bc10c 40 // Do a GET request to httpbin.org
Jan Jongboom 5:42f713b19337 41 {
Jan Jongboom 14:3c173847e681 42 // By default the body is automatically parsed and stored in a buffer, this is memory heavy.
Jan Jongboom 14:3c173847e681 43 // To receive chunked response, pass in a callback as last parameter to the constructor.
Jan Jongboom 5:42f713b19337 44 HttpRequest* get_req = new HttpRequest(network, HTTP_GET, "http://httpbin.org/status/418");
Jan Jongboom 0:85fdc69bc10c 45
Jan Jongboom 5:42f713b19337 46 HttpResponse* get_res = get_req->send();
Jan Jongboom 5:42f713b19337 47 if (!get_res) {
Jan Jongboom 5:42f713b19337 48 printf("HttpRequest failed (error code %d)\n", get_req->get_error());
Jan Jongboom 5:42f713b19337 49 return 1;
Jan Jongboom 5:42f713b19337 50 }
Jan Jongboom 5:42f713b19337 51
Jan Jongboom 5:42f713b19337 52 printf("\n----- HTTP GET response -----\n");
Jan Jongboom 5:42f713b19337 53 dump_response(get_res);
Jan Jongboom 5:42f713b19337 54
Jan Jongboom 5:42f713b19337 55 delete get_req;
Jan Jongboom 0:85fdc69bc10c 56 }
Jan Jongboom 0:85fdc69bc10c 57
Jan Jongboom 17:97b1dd566b07 58 mbed_stats_heap_get(&heap_stats);
Jan Jongboom 17:97b1dd566b07 59 printf("[3] Heap: %lu / %lu, max=%lu\n", heap_stats.current_size, heap_stats.reserved_size, heap_stats.max_size);
Jan Jongboom 17:97b1dd566b07 60
Jan Jongboom 0:85fdc69bc10c 61 // POST request to httpbin.org
Jan Jongboom 5:42f713b19337 62 {
Jan Jongboom 5:42f713b19337 63 HttpRequest* post_req = new HttpRequest(network, HTTP_POST, "http://httpbin.org/post");
Jan Jongboom 5:42f713b19337 64 post_req->set_header("Content-Type", "application/json");
Jan Jongboom 0:85fdc69bc10c 65
Jan Jongboom 5:42f713b19337 66 const char body[] = "{\"hello\":\"world\"}";
Jan Jongboom 0:85fdc69bc10c 67
Jan Jongboom 5:42f713b19337 68 HttpResponse* post_res = post_req->send(body, strlen(body));
Jan Jongboom 5:42f713b19337 69 if (!post_res) {
Jan Jongboom 5:42f713b19337 70 printf("HttpRequest failed (error code %d)\n", post_req->get_error());
Jan Jongboom 5:42f713b19337 71 return 1;
Jan Jongboom 5:42f713b19337 72 }
Jan Jongboom 5:42f713b19337 73
Jan Jongboom 5:42f713b19337 74 printf("\n----- HTTP POST response -----\n");
Jan Jongboom 5:42f713b19337 75 dump_response(post_res);
Jan Jongboom 5:42f713b19337 76
Jan Jongboom 17:97b1dd566b07 77 mbed_stats_heap_get(&heap_stats);
Jan Jongboom 17:97b1dd566b07 78 printf("[4] Heap: %lu / %lu, max=%lu\n", heap_stats.current_size, heap_stats.reserved_size, heap_stats.max_size);
Jan Jongboom 17:97b1dd566b07 79
Jan Jongboom 5:42f713b19337 80 delete post_req;
Jan Jongboom 0:85fdc69bc10c 81 }
Jan Jongboom 0:85fdc69bc10c 82
Jan Jongboom 17:97b1dd566b07 83 mbed_stats_heap_get(&heap_stats);
Jan Jongboom 17:97b1dd566b07 84 printf("[5] Heap: %lu / %lu, max=%lu\n", heap_stats.current_size, heap_stats.reserved_size, heap_stats.max_size);
Jan Jongboom 17:97b1dd566b07 85
Jan Jongboom 0:85fdc69bc10c 86 Thread::wait(osWaitForever);
Jan Jongboom 0:85fdc69bc10c 87 }
Jan Jongboom 0:85fdc69bc10c 88
Jan Jongboom 0:85fdc69bc10c 89 #endif