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- /* Feel free to use this example code in any way
- you see fit (Public Domain) */
- /* needed for asprintf */
- #define _GNU_SOURCE
- #include <stdlib.h>
- #include <string.h>
- #include <stdio.h>
- #include <errno.h>
- #include <time.h>
- #include <microhttpd.h>
- #if defined _WIN32 && !defined(__MINGW64_VERSION_MAJOR)
- static int
- asprintf (char **resultp, const char *format, ...)
- {
- va_list argptr;
- char *result = NULL;
- int len = 0;
- if (format == NULL)
- return -1;
- va_start (argptr, format);
- len = _vscprintf ((char *) format, argptr);
- if (len >= 0)
- {
- len += 1;
- result = (char *) malloc (sizeof (char *) * len);
- if (result != NULL)
- {
- int len2 = _vscprintf ((char *) format, argptr);
- if (len2 != len - 1 || len2 <= 0)
- {
- free (result);
- result = NULL;
- len = -1;
- }
- else
- {
- len = len2;
- if (resultp)
- *resultp = result;
- }
- }
- }
- va_end (argptr);
- return len;
- }
- #endif
- /**
- * Invalid method page.
- */
- #define METHOD_ERROR "<html><head><title>Illegal request</title></head><body>Go away.</body></html>"
- /**
- * Invalid URL page.
- */
- #define NOT_FOUND_ERROR "<html><head><title>Not found</title></head><body>Go away.</body></html>"
- /**
- * Front page. (/)
- */
- #define MAIN_PAGE "<html><head><title>Welcome</title></head><body><form action=\"/2\" method=\"post\">What is your name? <input type=\"text\" name=\"v1\" value=\"%s\" /><input type=\"submit\" value=\"Next\" /></body></html>"
- /**
- * Second page. (/2)
- */
- #define SECOND_PAGE "<html><head><title>Tell me more</title></head><body><a href=\"/\">previous</a> <form action=\"/S\" method=\"post\">%s, what is your job? <input type=\"text\" name=\"v2\" value=\"%s\" /><input type=\"submit\" value=\"Next\" /></body></html>"
- /**
- * Second page (/S)
- */
- #define SUBMIT_PAGE "<html><head><title>Ready to submit?</title></head><body><form action=\"/F\" method=\"post\"><a href=\"/2\">previous </a> <input type=\"hidden\" name=\"DONE\" value=\"yes\" /><input type=\"submit\" value=\"Submit\" /></body></html>"
- /**
- * Last page.
- */
- #define LAST_PAGE "<html><head><title>Thank you</title></head><body>Thank you.</body></html>"
- /**
- * Name of our cookie.
- */
- #define COOKIE_NAME "session"
- /**
- * State we keep for each user/session/browser.
- */
- struct Session
- {
- /**
- * We keep all sessions in a linked list.
- */
- struct Session *next;
- /**
- * Unique ID for this session.
- */
- char sid[33];
- /**
- * Reference counter giving the number of connections
- * currently using this session.
- */
- unsigned int rc;
- /**
- * Time when this session was last active.
- */
- time_t start;
- /**
- * String submitted via form.
- */
- char value_1[64];
- /**
- * Another value submitted via form.
- */
- char value_2[64];
- };
- /**
- * Data kept per request.
- */
- struct Request
- {
- /**
- * Associated session.
- */
- struct Session *session;
- /**
- * Post processor handling form data (IF this is
- * a POST request).
- */
- struct MHD_PostProcessor *pp;
- /**
- * URL to serve in response to this POST (if this request
- * was a 'POST')
- */
- const char *post_url;
- };
- /**
- * Linked list of all active sessions. Yes, O(n) but a
- * hash table would be overkill for a simple example...
- */
- static struct Session *sessions;
- /**
- * Return the session handle for this connection, or
- * create one if this is a new user.
- */
- static struct Session *
- get_session (struct MHD_Connection *connection)
- {
- struct Session *ret;
- const char *cookie;
- cookie = MHD_lookup_connection_value (connection,
- MHD_COOKIE_KIND,
- COOKIE_NAME);
- if (cookie != NULL)
- {
- /* find existing session */
- ret = sessions;
- while (NULL != ret)
- {
- if (0 == strcmp (cookie, ret->sid))
- break;
- ret = ret->next;
- }
- if (NULL != ret)
- {
- ret->rc++;
- return ret;
- }
- }
- /* create fresh session */
- ret = calloc (1, sizeof (struct Session));
- if (NULL == ret)
- {
- fprintf (stderr, "calloc error: %s\n", strerror (errno));
- return NULL;
- }
- /* not a super-secure way to generate a random session ID,
- but should do for a simple example... */
- snprintf (ret->sid,
- sizeof (ret->sid),
- "%X%X%X%X",
- (unsigned int) rand (),
- (unsigned int) rand (),
- (unsigned int) rand (),
- (unsigned int) rand ());
- ret->rc++;
- ret->start = time (NULL);
- ret->next = sessions;
- sessions = ret;
- return ret;
- }
- /**
- * Type of handler that generates a reply.
- *
- * @param cls content for the page (handler-specific)
- * @param mime mime type to use
- * @param session session information
- * @param connection connection to process
- * @param MHD_YES on success, MHD_NO on failure
- */
- typedef int (*PageHandler)(const void *cls,
- const char *mime,
- struct Session *session,
- struct MHD_Connection *connection);
- /**
- * Entry we generate for each page served.
- */
- struct Page
- {
- /**
- * Acceptable URL for this page.
- */
- const char *url;
- /**
- * Mime type to set for the page.
- */
- const char *mime;
- /**
- * Handler to call to generate response.
- */
- PageHandler handler;
- /**
- * Extra argument to handler.
- */
- const void *handler_cls;
- };
- /**
- * Add header to response to set a session cookie.
- *
- * @param session session to use
- * @param response response to modify
- */
- static void
- add_session_cookie (struct Session *session,
- struct MHD_Response *response)
- {
- char cstr[256];
- snprintf (cstr,
- sizeof (cstr),
- "%s=%s",
- COOKIE_NAME,
- session->sid);
- if (MHD_NO ==
- MHD_add_response_header (response,
- MHD_HTTP_HEADER_SET_COOKIE,
- cstr))
- {
- fprintf (stderr,
- "Failed to set session cookie header!\n");
- }
- }
- /**
- * Handler that returns a simple static HTTP page that
- * is passed in via 'cls'.
- *
- * @param cls a 'const char *' with the HTML webpage to return
- * @param mime mime type to use
- * @param session session handle
- * @param connection connection to use
- */
- static int
- serve_simple_form (const void *cls,
- const char *mime,
- struct Session *session,
- struct MHD_Connection *connection)
- {
- int ret;
- const char *form = cls;
- struct MHD_Response *response;
- /* return static form */
- response = MHD_create_response_from_buffer (strlen (form),
- (void *) form,
- MHD_RESPMEM_PERSISTENT);
- add_session_cookie (session, response);
- MHD_add_response_header (response,
- MHD_HTTP_HEADER_CONTENT_ENCODING,
- mime);
- ret = MHD_queue_response (connection,
- MHD_HTTP_OK,
- response);
- MHD_destroy_response (response);
- return ret;
- }
- /**
- * Handler that adds the 'v1' value to the given HTML code.
- *
- * @param cls a 'const char *' with the HTML webpage to return
- * @param mime mime type to use
- * @param session session handle
- * @param connection connection to use
- */
- static int
- fill_v1_form (const void *cls,
- const char *mime,
- struct Session *session,
- struct MHD_Connection *connection)
- {
- int ret;
- const char *form = cls;
- char *reply;
- struct MHD_Response *response;
- if (-1 == asprintf (&reply,
- form,
- session->value_1))
- {
- /* oops */
- return MHD_NO;
- }
- /* return static form */
- response = MHD_create_response_from_buffer (strlen (reply),
- (void *) reply,
- MHD_RESPMEM_MUST_FREE);
- add_session_cookie (session, response);
- MHD_add_response_header (response,
- MHD_HTTP_HEADER_CONTENT_ENCODING,
- mime);
- ret = MHD_queue_response (connection,
- MHD_HTTP_OK,
- response);
- MHD_destroy_response (response);
- return ret;
- }
- /**
- * Handler that adds the 'v1' and 'v2' values to the given HTML code.
- *
- * @param cls a 'const char *' with the HTML webpage to return
- * @param mime mime type to use
- * @param session session handle
- * @param connection connection to use
- */
- static int
- fill_v1_v2_form (const void *cls,
- const char *mime,
- struct Session *session,
- struct MHD_Connection *connection)
- {
- int ret;
- const char *form = cls;
- char *reply;
- struct MHD_Response *response;
- if (-1 == asprintf (&reply,
- form,
- session->value_1,
- session->value_2))
- {
- /* oops */
- return MHD_NO;
- }
- /* return static form */
- response = MHD_create_response_from_buffer (strlen (reply),
- (void *) reply,
- MHD_RESPMEM_MUST_FREE);
- add_session_cookie (session, response);
- MHD_add_response_header (response,
- MHD_HTTP_HEADER_CONTENT_ENCODING,
- mime);
- ret = MHD_queue_response (connection,
- MHD_HTTP_OK,
- response);
- MHD_destroy_response (response);
- return ret;
- }
- /**
- * Handler used to generate a 404 reply.
- *
- * @param cls a 'const char *' with the HTML webpage to return
- * @param mime mime type to use
- * @param session session handle
- * @param connection connection to use
- */
- static int
- not_found_page (const void *cls,
- const char *mime,
- struct Session *session,
- struct MHD_Connection *connection)
- {
- int ret;
- struct MHD_Response *response;
- (void)cls; /* Unused. Silent compiler warning. */
- (void)session; /* Unused. Silent compiler warning. */
- /* unsupported HTTP method */
- response = MHD_create_response_from_buffer (strlen (NOT_FOUND_ERROR),
- (void *) NOT_FOUND_ERROR,
- MHD_RESPMEM_PERSISTENT);
- ret = MHD_queue_response (connection,
- MHD_HTTP_NOT_FOUND,
- response);
- MHD_add_response_header (response,
- MHD_HTTP_HEADER_CONTENT_ENCODING,
- mime);
- MHD_destroy_response (response);
- return ret;
- }
- /**
- * List of all pages served by this HTTP server.
- */
- static struct Page pages[] =
- {
- { "/", "text/html", &fill_v1_form, MAIN_PAGE },
- { "/2", "text/html", &fill_v1_v2_form, SECOND_PAGE },
- { "/S", "text/html", &serve_simple_form, SUBMIT_PAGE },
- { "/F", "text/html", &serve_simple_form, LAST_PAGE },
- { NULL, NULL, ¬_found_page, NULL } /* 404 */
- };
- /**
- * Iterator over key-value pairs where the value
- * maybe made available in increments and/or may
- * not be zero-terminated. Used for processing
- * POST data.
- *
- * @param cls user-specified closure
- * @param kind type of the value
- * @param key 0-terminated key for the value
- * @param filename name of the uploaded file, NULL if not known
- * @param content_type mime-type of the data, NULL if not known
- * @param transfer_encoding encoding of the data, NULL if not known
- * @param data pointer to size bytes of data at the
- * specified offset
- * @param off offset of data in the overall value
- * @param size number of bytes in data available
- * @return MHD_YES to continue iterating,
- * MHD_NO to abort the iteration
- */
- static int
- post_iterator (void *cls,
- enum MHD_ValueKind kind,
- const char *key,
- const char *filename,
- const char *content_type,
- const char *transfer_encoding,
- const char *data, uint64_t off, size_t size)
- {
- struct Request *request = cls;
- struct Session *session = request->session;
- (void)kind; /* Unused. Silent compiler warning. */
- (void)filename; /* Unused. Silent compiler warning. */
- (void)content_type; /* Unused. Silent compiler warning. */
- (void)transfer_encoding; /* Unused. Silent compiler warning. */
- if (0 == strcmp ("DONE", key))
- {
- fprintf (stdout,
- "Session `%s' submitted `%s', `%s'\n",
- session->sid,
- session->value_1,
- session->value_2);
- return MHD_YES;
- }
- if (0 == strcmp ("v1", key))
- {
- if (size + off > sizeof(session->value_1))
- size = sizeof (session->value_1) - off;
- memcpy (&session->value_1[off],
- data,
- size);
- if (size + off < sizeof (session->value_1))
- session->value_1[size+off] = '\0';
- return MHD_YES;
- }
- if (0 == strcmp ("v2", key))
- {
- if (size + off > sizeof(session->value_2))
- size = sizeof (session->value_2) - off;
- memcpy (&session->value_2[off],
- data,
- size);
- if (size + off < sizeof (session->value_2))
- session->value_2[size+off] = '\0';
- return MHD_YES;
- }
- fprintf (stderr, "Unsupported form value `%s'\n", key);
- return MHD_YES;
- }
- /**
- * Main MHD callback for handling requests.
- *
- *
- * @param cls argument given together with the function
- * pointer when the handler was registered with MHD
- * @param connection handle to connection which is being processed
- * @param url the requested url
- * @param method the HTTP method used ("GET", "PUT", etc.)
- * @param version the HTTP version string (i.e. "HTTP/1.1")
- * @param upload_data the data being uploaded (excluding HEADERS,
- * for a POST that fits into memory and that is encoded
- * with a supported encoding, the POST data will NOT be
- * given in upload_data and is instead available as
- * part of MHD_get_connection_values; very large POST
- * data *will* be made available incrementally in
- * upload_data)
- * @param upload_data_size set initially to the size of the
- * upload_data provided; the method must update this
- * value to the number of bytes NOT processed;
- * @param ptr pointer that the callback can set to some
- * address and that will be preserved by MHD for future
- * calls for this request; since the access handler may
- * be called many times (i.e., for a PUT/POST operation
- * with plenty of upload data) this allows the application
- * to easily associate some request-specific state.
- * If necessary, this state can be cleaned up in the
- * global "MHD_RequestCompleted" callback (which
- * can be set with the MHD_OPTION_NOTIFY_COMPLETED).
- * Initially, <tt>*con_cls</tt> will be NULL.
- * @return MHS_YES if the connection was handled successfully,
- * MHS_NO if the socket must be closed due to a serios
- * error while handling the request
- */
- static int
- create_response (void *cls,
- struct MHD_Connection *connection,
- const char *url,
- const char *method,
- const char *version,
- const char *upload_data,
- size_t *upload_data_size,
- void **ptr)
- {
- struct MHD_Response *response;
- struct Request *request;
- struct Session *session;
- int ret;
- unsigned int i;
- (void)cls; /* Unused. Silent compiler warning. */
- (void)version; /* Unused. Silent compiler warning. */
- request = *ptr;
- if (NULL == request)
- {
- request = calloc (1, sizeof (struct Request));
- if (NULL == request)
- {
- fprintf (stderr, "calloc error: %s\n", strerror (errno));
- return MHD_NO;
- }
- *ptr = request;
- if (0 == strcmp (method, MHD_HTTP_METHOD_POST))
- {
- request->pp = MHD_create_post_processor (connection, 1024,
- &post_iterator, request);
- if (NULL == request->pp)
- {
- fprintf (stderr, "Failed to setup post processor for `%s'\n",
- url);
- return MHD_NO; /* internal error */
- }
- }
- return MHD_YES;
- }
- if (NULL == request->session)
- {
- request->session = get_session (connection);
- if (NULL == request->session)
- {
- fprintf (stderr, "Failed to setup session for `%s'\n",
- url);
- return MHD_NO; /* internal error */
- }
- }
- session = request->session;
- session->start = time (NULL);
- if (0 == strcmp (method, MHD_HTTP_METHOD_POST))
- {
- /* evaluate POST data */
- MHD_post_process (request->pp,
- upload_data,
- *upload_data_size);
- if (0 != *upload_data_size)
- {
- *upload_data_size = 0;
- return MHD_YES;
- }
- /* done with POST data, serve response */
- MHD_destroy_post_processor (request->pp);
- request->pp = NULL;
- method = MHD_HTTP_METHOD_GET; /* fake 'GET' */
- if (NULL != request->post_url)
- url = request->post_url;
- }
- if ( (0 == strcmp (method, MHD_HTTP_METHOD_GET)) ||
- (0 == strcmp (method, MHD_HTTP_METHOD_HEAD)) )
- {
- /* find out which page to serve */
- i=0;
- while ( (pages[i].url != NULL) &&
- (0 != strcmp (pages[i].url, url)) )
- i++;
- ret = pages[i].handler (pages[i].handler_cls,
- pages[i].mime,
- session, connection);
- if (ret != MHD_YES)
- fprintf (stderr, "Failed to create page for `%s'\n",
- url);
- return ret;
- }
- /* unsupported HTTP method */
- response = MHD_create_response_from_buffer (strlen (METHOD_ERROR),
- (void *) METHOD_ERROR,
- MHD_RESPMEM_PERSISTENT);
- ret = MHD_queue_response (connection,
- MHD_HTTP_NOT_ACCEPTABLE,
- response);
- MHD_destroy_response (response);
- return ret;
- }
- /**
- * Callback called upon completion of a request.
- * Decrements session reference counter.
- *
- * @param cls not used
- * @param connection connection that completed
- * @param con_cls session handle
- * @param toe status code
- */
- static void
- request_completed_callback (void *cls,
- struct MHD_Connection *connection,
- void **con_cls,
- enum MHD_RequestTerminationCode toe)
- {
- struct Request *request = *con_cls;
- (void)cls; /* Unused. Silent compiler warning. */
- (void)connection; /* Unused. Silent compiler warning. */
- (void)toe; /* Unused. Silent compiler warning. */
- if (NULL == request)
- return;
- if (NULL != request->session)
- request->session->rc--;
- if (NULL != request->pp)
- MHD_destroy_post_processor (request->pp);
- free (request);
- }
- /**
- * Clean up handles of sessions that have been idle for
- * too long.
- */
- static void
- expire_sessions ()
- {
- struct Session *pos;
- struct Session *prev;
- struct Session *next;
- time_t now;
- now = time (NULL);
- prev = NULL;
- pos = sessions;
- while (NULL != pos)
- {
- next = pos->next;
- if (now - pos->start > 60 * 60)
- {
- /* expire sessions after 1h */
- if (NULL == prev)
- sessions = pos->next;
- else
- prev->next = next;
- free (pos);
- }
- else
- prev = pos;
- pos = next;
- }
- }
- /**
- * Call with the port number as the only argument.
- * Never terminates (other than by signals, such as CTRL-C).
- */
- int
- main (int argc, char *const *argv)
- {
- struct MHD_Daemon *d;
- struct timeval tv;
- struct timeval *tvp;
- fd_set rs;
- fd_set ws;
- fd_set es;
- MHD_socket max;
- MHD_UNSIGNED_LONG_LONG mhd_timeout;
- if (argc != 2)
- {
- printf ("%s PORT\n", argv[0]);
- return 1;
- }
- /* initialize PRNG */
- srand ((unsigned int) time (NULL));
- d = MHD_start_daemon (MHD_USE_ERROR_LOG,
- atoi (argv[1]),
- NULL, NULL,
- &create_response, NULL,
- MHD_OPTION_CONNECTION_TIMEOUT, (unsigned int) 15,
- MHD_OPTION_NOTIFY_COMPLETED, &request_completed_callback, NULL,
- MHD_OPTION_END);
- if (NULL == d)
- return 1;
- while (1)
- {
- expire_sessions ();
- max = 0;
- FD_ZERO (&rs);
- FD_ZERO (&ws);
- FD_ZERO (&es);
- if (MHD_YES != MHD_get_fdset (d, &rs, &ws, &es, &max))
- break; /* fatal internal error */
- if (MHD_get_timeout (d, &mhd_timeout) == MHD_YES)
- {
- tv.tv_sec = mhd_timeout / 1000;
- tv.tv_usec = (mhd_timeout - (tv.tv_sec * 1000)) * 1000;
- tvp = &tv;
- }
- else
- tvp = NULL;
- if (-1 == select (max + 1, &rs, &ws, &es, tvp))
- {
- if (EINTR != errno)
- fprintf (stderr,
- "Aborting due to error during select: %s\n",
- strerror (errno));
- break;
- }
- MHD_run (d);
- }
- MHD_stop_daemon (d);
- return 0;
- }
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