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:
- HTTP:
- Does a GET request to http:httpbin.org/status/418.
- Does a POST request to http:httpbin.org/post.
- HTTPS:
- Does a GET request to https:os.mbed.com/media/uploads/mbed_official/hello.txt.
- Does a POST request to https:httpbin.org/post.
- HTTP with socket re-use.
- HTTPS with socket re-use.
- HTTP over IPv6.
- HTTPS with chunked requests.
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
- If you're using WiFi, specify the credentials in
mbed_app.json. - Build the project in the online compiler or using Mbed CLI.
- Flash the project to your development board.
- 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.
- In
select-demo.hset theDEMOmacro toDEMO_TESTS. - Set your WiFi credentials in
mbed_app.json. - 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).
Diff: source/mbed-http/https_request.h
- Revision:
- 2:4b4ac59ff9b0
- Parent:
- 1:3bff14db67c7
- Child:
- 3:0f5859a9e3de
diff -r 3bff14db67c7 -r 4b4ac59ff9b0 source/mbed-http/https_request.h
--- a/source/mbed-http/https_request.h Thu Feb 16 11:13:40 2017 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,428 +0,0 @@
-#ifndef _MBED_HTTPS_REQUEST_H_
-#define _MBED_HTTPS_REQUEST_H_
-
-/* Change to a number between 1 and 4 to debug the TLS connection */
-#define DEBUG_LEVEL 0
-
-#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"
-
-#include "mbedtls/platform.h"
-#include "mbedtls/ssl.h"
-#include "mbedtls/entropy.h"
-#include "mbedtls/ctr_drbg.h"
-#include "mbedtls/error.h"
-
-#if DEBUG_LEVEL > 0
-#include "mbedtls/debug.h"
-#endif
-
-/**
- * \brief HttpsRequest implements the logic for interacting with HTTPS servers.
- */
-class HttpsRequest {
-public:
- /**
- * HttpsRequest Constructor
- * Initializes the TCP socket, sets up event handlers and flags.
- *
- * @param[in] net_iface The network interface
- * @param[in] ssl_ca_pem String containing the trusted CAs
- * @param[in] method HTTP method to use
- * @param[in] url URL to the resource
- * @param[in] body_callback 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.
- */
- HttpsRequest(NetworkInterface* net_iface,
- const char* ssl_ca_pem,
- http_method method,
- const char* url,
- Callback<void(const char *at, size_t length)> body_callback = 0)
- {
- _parsed_url = new ParsedUrl(url);
- _body_callback = body_callback;
- _tcpsocket = new TCPSocket(net_iface);
- _request_builder = new HttpRequestBuilder(method, _parsed_url);
- _response = NULL;
- _debug = false;
- _ssl_ca_pem = ssl_ca_pem;
-
- DRBG_PERS = "mbed TLS helloword client";
-
- mbedtls_entropy_init(&_entropy);
- mbedtls_ctr_drbg_init(&_ctr_drbg);
- mbedtls_x509_crt_init(&_cacert);
- mbedtls_ssl_init(&_ssl);
- mbedtls_ssl_config_init(&_ssl_conf);
- }
-
- /**
- * HttpsRequest Destructor
- */
- ~HttpsRequest() {
- mbedtls_entropy_free(&_entropy);
- mbedtls_ctr_drbg_free(&_ctr_drbg);
- mbedtls_x509_crt_free(&_cacert);
- mbedtls_ssl_free(&_ssl);
- mbedtls_ssl_config_free(&_ssl_conf);
-
- if (_request_builder) {
- delete _request_builder;
- }
-
- if (_tcpsocket) {
- delete _tcpsocket;
- }
-
- if (_parsed_url) {
- delete _parsed_url;
- }
-
- if (_response) {
- delete _response;
- }
-
- // @todo: free DRBG_PERS ?
- }
-
- /**
- * Execute the HTTPS request.
- *
- * @param[in] body Pointer to the request body
- * @param[in] body_size Size of the request body
- * @return An HttpResponse pointer on success, or NULL on failure.
- * See get_error() for the error code.
- */
- HttpResponse* send(const void* body = NULL, nsapi_size_t body_size = 0) {
- /* Initialize the flags */
- /*
- * Initialize TLS-related stuf.
- */
- int ret;
- if ((ret = mbedtls_ctr_drbg_seed(&_ctr_drbg, mbedtls_entropy_func, &_entropy,
- (const unsigned char *) DRBG_PERS,
- sizeof (DRBG_PERS))) != 0) {
- print_mbedtls_error("mbedtls_crt_drbg_init", ret);
- _error = ret;
- return NULL;
- }
-
- if ((ret = mbedtls_x509_crt_parse(&_cacert, (const unsigned char *)_ssl_ca_pem,
- strlen(_ssl_ca_pem) + 1)) != 0) {
- print_mbedtls_error("mbedtls_x509_crt_parse", ret);
- _error = ret;
- return NULL;
- }
-
- if ((ret = mbedtls_ssl_config_defaults(&_ssl_conf,
- MBEDTLS_SSL_IS_CLIENT,
- MBEDTLS_SSL_TRANSPORT_STREAM,
- MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
- print_mbedtls_error("mbedtls_ssl_config_defaults", ret);
- _error = ret;
- return NULL;
- }
-
- mbedtls_ssl_conf_ca_chain(&_ssl_conf, &_cacert, NULL);
- mbedtls_ssl_conf_rng(&_ssl_conf, mbedtls_ctr_drbg_random, &_ctr_drbg);
-
- /* It is possible to disable authentication by passing
- * MBEDTLS_SSL_VERIFY_NONE in the call to mbedtls_ssl_conf_authmode()
- */
- mbedtls_ssl_conf_authmode(&_ssl_conf, MBEDTLS_SSL_VERIFY_REQUIRED);
-
-#if DEBUG_LEVEL > 0
- mbedtls_ssl_conf_verify(&_ssl_conf, my_verify, NULL);
- mbedtls_ssl_conf_dbg(&_ssl_conf, my_debug, NULL);
- mbedtls_debug_set_threshold(DEBUG_LEVEL);
-#endif
-
- if ((ret = mbedtls_ssl_setup(&_ssl, &_ssl_conf)) != 0) {
- print_mbedtls_error("mbedtls_ssl_setup", ret);
- _error = ret;
- return NULL;
- }
-
- mbedtls_ssl_set_hostname(&_ssl, _parsed_url->host());
-
- mbedtls_ssl_set_bio(&_ssl, static_cast<void *>(_tcpsocket),
- ssl_send, ssl_recv, NULL );
-
- /* Connect to the server */
- if (_debug) mbedtls_printf("Connecting to %s:%d\r\n", _parsed_url->host(), _parsed_url->port());
- ret = _tcpsocket->connect(_parsed_url->host(), _parsed_url->port());
- if (ret != NSAPI_ERROR_OK) {
- if (_debug) mbedtls_printf("Failed to connect\r\n");
- onError(_tcpsocket, -1);
- return NULL;
- }
-
- /* Start the handshake, the rest will be done in onReceive() */
- if (_debug) mbedtls_printf("Starting the TLS handshake...\r\n");
- ret = mbedtls_ssl_handshake(&_ssl);
- if (ret < 0) {
- if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
- ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
- print_mbedtls_error("mbedtls_ssl_handshake", ret);
- onError(_tcpsocket, -1);
- }
- else {
- _error = ret;
- }
- return NULL;
- }
-
- char* request = _request_builder->build(body, body_size);
- size_t request_size = strlen(request);
-
- ret = mbedtls_ssl_write(&_ssl, (const unsigned char *) request, request_size);
-
- free(request);
-
- if (ret < 0) {
- if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
- ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
- print_mbedtls_error("mbedtls_ssl_write", ret);
- onError(_tcpsocket, -1 );
- }
- else {
- _error = ret;
- }
- return NULL;
- }
-
- /* It also means the handshake is done, time to print info */
- if (_debug) mbedtls_printf("TLS connection to %s:%d established\r\n", _parsed_url->host(), _parsed_url->port());
-
- const uint32_t buf_size = 1024;
- char *buf = new char[buf_size];
- mbedtls_x509_crt_info(buf, buf_size, "\r ",
- mbedtls_ssl_get_peer_cert(&_ssl));
- if (_debug) mbedtls_printf("Server certificate:\r\n%s\r", buf);
-
- uint32_t flags = mbedtls_ssl_get_verify_result(&_ssl);
- if( flags != 0 )
- {
- mbedtls_x509_crt_verify_info(buf, buf_size, "\r ! ", flags);
- if (_debug) mbedtls_printf("Certificate verification failed:\r\n%s\r\r\n", buf);
- }
- else {
- if (_debug) mbedtls_printf("Certificate verification passed\r\n\r\n");
- }
-
- // 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);
-
- /* Read data out of the socket */
- while ((ret = mbedtls_ssl_read(&_ssl, (unsigned char *) recv_buffer, HTTP_RECEIVE_BUFFER_SIZE)) > 0) {
- // Don't know if this is actually needed, but OK
- size_t _bpos = static_cast<size_t>(ret);
- recv_buffer[_bpos] = 0;
-
- size_t nparsed = parser.execute((const char*)recv_buffer, _bpos);
- if (nparsed != _bpos) {
- print_mbedtls_error("parser_error", nparsed);
- // parser error...
- _error = -2101;
- free(recv_buffer);
- return NULL;
- }
- // No more chunks? break out of this loop
- if (_bpos < HTTP_RECEIVE_BUFFER_SIZE) {
- break;
- }
- }
- if (ret < 0) {
- if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
- print_mbedtls_error("mbedtls_ssl_read", ret);
- onError(_tcpsocket, -1 );
- }
- else {
- _error = ret;
- }
- free(recv_buffer);
- return NULL;
- }
-
- parser.finish();
-
- _tcpsocket->close();
- free(recv_buffer);
-
- return _response;
- }
-
- /**
- * Closes the TCP socket
- */
- void close() {
- _tcpsocket->close();
- }
-
- /**
- * 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;
- }
-
- /**
- * Set the debug flag.
- *
- * If this flag is set, debug information from mbed TLS will be logged to stdout.
- */
- void set_debug(bool debug) {
- _debug = debug;
- }
-
-protected:
- /**
- * Helper for pretty-printing mbed TLS error codes
- */
- static void print_mbedtls_error(const char *name, int err) {
- char buf[128];
- mbedtls_strerror(err, buf, sizeof (buf));
- mbedtls_printf("%s() failed: -0x%04x (%d): %s\r\n", name, -err, err, buf);
- }
-
-#if DEBUG_LEVEL > 0
- /**
- * Debug callback for mbed TLS
- * Just prints on the USB serial port
- */
- static void my_debug(void *ctx, int level, const char *file, int line,
- const char *str)
- {
- const char *p, *basename;
- (void) ctx;
-
- /* Extract basename from file */
- for(p = basename = file; *p != '\0'; p++) {
- if(*p == '/' || *p == '\\') {
- basename = p + 1;
- }
- }
-
- if (_debug) {
- mbedtls_printf("%s:%04d: |%d| %s", basename, line, level, str);
- }
- }
-
- /**
- * Certificate verification callback for mbed TLS
- * Here we only use it to display information on each cert in the chain
- */
- static int my_verify(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags)
- {
- const uint32_t buf_size = 1024;
- char *buf = new char[buf_size];
- (void) data;
-
- if (_debug) mbedtls_printf("\nVerifying certificate at depth %d:\n", depth);
- mbedtls_x509_crt_info(buf, buf_size - 1, " ", crt);
- if (_debug) mbedtls_printf("%s", buf);
-
- if (*flags == 0)
- if (_debug) mbedtls_printf("No verification issue for this certificate\n");
- else
- {
- mbedtls_x509_crt_verify_info(buf, buf_size, " ! ", *flags);
- if (_debug) mbedtls_printf("%s\n", buf);
- }
-
- delete[] buf;
- return 0;
- }
-#endif
-
- /**
- * Receive callback for mbed TLS
- */
- static int ssl_recv(void *ctx, unsigned char *buf, size_t len) {
- int recv = -1;
- TCPSocket *socket = static_cast<TCPSocket *>(ctx);
- recv = socket->recv(buf, len);
-
- if (NSAPI_ERROR_WOULD_BLOCK == recv) {
- return MBEDTLS_ERR_SSL_WANT_READ;
- }
- else if (recv < 0) {
- return -1;
- }
- else {
- return recv;
- }
- }
-
- /**
- * Send callback for mbed TLS
- */
- static int ssl_send(void *ctx, const unsigned char *buf, size_t len) {
- int size = -1;
- TCPSocket *socket = static_cast<TCPSocket *>(ctx);
- size = socket->send(buf, len);
-
- if(NSAPI_ERROR_WOULD_BLOCK == size) {
- return len;
- }
- else if (size < 0){
- return -1;
- }
- else {
- return size;
- }
- }
-
- void onError(TCPSocket *s, int error) {
- s->close();
- _error = error;
- }
-
-protected:
- TCPSocket* _tcpsocket;
-
- Callback<void(const char *at, size_t length)> _body_callback;
- ParsedUrl* _parsed_url;
- HttpRequestBuilder* _request_builder;
- HttpResponse* _response;
- const char *DRBG_PERS;
- const char *_ssl_ca_pem;
-
- nsapi_error_t _error;
- bool _debug;
-
- mbedtls_entropy_context _entropy;
- mbedtls_ctr_drbg_context _ctr_drbg;
- mbedtls_x509_crt _cacert;
- mbedtls_ssl_context _ssl;
- mbedtls_ssl_config _ssl_conf;
-};
-
-#endif // _MBED_HTTPS_REQUEST_H_