zoneminder/src/zm_curl_camera.cpp

//
// ZoneMinder cURL Camera Class Implementation, $Date: 2009-01-16 12:18:50 +0000 (Fri, 16 Jan 2009) $, $Revision: 2713 $
// Copyright (C) 2001-2008 Philip Coombes
// 
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
// 

#include "zm.h"
#include "zm_curl_camera.h"

#if HAVE_LIBCURL

#define CURL_MAXRETRY 5
#define CURL_BUFFER_INITIAL_SIZE 65536

const char* content_length_match = "Content-Length:";
const char* content_type_match = "Content-Type:";
size_t content_length_match_len;
size_t content_type_match_len;

cURLCamera::cURLCamera( int p_id, const std::string &p_path, const std::string &p_user, const std::string &p_pass, int p_width, int p_height, int p_colours, int p_brightness, int p_contrast, int p_hue, int p_colour, bool p_capture ) :
    Camera( p_id, CURL_SRC, p_width, p_height, p_colours, ZM_SUBPIX_ORDER_DEFAULT_FOR_COLOUR(p_colours), p_brightness, p_contrast, p_hue, p_colour, p_capture ),
    mPath( p_path ), mUser( p_user ), mPass ( p_pass ), bTerminate( false ), bReset( false ), mode ( MODE_UNSET )
{

	if ( capture )
	{
		Initialise();
	}
}

cURLCamera::~cURLCamera()
{
	if ( capture )
	{

		Terminate();
	}
}

void cURLCamera::Initialise()
{
	content_length_match_len = strlen(content_length_match);
	content_type_match_len = strlen(content_type_match);

	databuffer.expand(CURL_BUFFER_INITIAL_SIZE);

	/* cURL initialization */
	cRet = curl_global_init(CURL_GLOBAL_ALL);
	if(cRet != CURLE_OK) {
		Fatal("libcurl initialization failed: ", curl_easy_strerror(cRet));
	}

	Debug(2,"libcurl version: %s",curl_version());

	/* Create the shared data mutex */
	nRet = pthread_mutex_init(&shareddata_mutex, NULL);
	if(nRet != 0) {
		Fatal("Shared data mutex creation failed: %s",strerror(nRet));
	}
	/* Create the data available condition variable */
	nRet = pthread_cond_init(&data_available_cond, NULL);
	if(nRet != 0) {
		Fatal("Data available condition variable creation failed: %s",strerror(nRet));
	}
	/* Create the request complete condition variable */
	nRet = pthread_cond_init(&request_complete_cond, NULL);
	if(nRet != 0) {
		Fatal("Request complete condition variable creation failed: %s",strerror(nRet));
	}

	/* Create the thread */
	nRet = pthread_create(&thread, NULL, thread_func_dispatcher, this);
	if(nRet != 0) {
		Fatal("Thread creation failed: %s",strerror(nRet));
	}
}

void cURLCamera::Terminate()
{
	/* Signal the thread to terminate */
	bTerminate = true;

	/* Wait for thread termination */
	pthread_join(thread, NULL);

	/* Destroy condition variables */
	pthread_cond_destroy(&request_complete_cond);
	pthread_cond_destroy(&data_available_cond);

	/* Destroy mutex */
	pthread_mutex_destroy(&shareddata_mutex);

	/* cURL cleanup */
	curl_global_cleanup();

}

int cURLCamera::PrimeCapture()
{
	//Info( "Priming capture from %s", mPath.c_str() );
	return 0;
}

int cURLCamera::PreCapture()
{
    // Nothing to do here
    return( 0 );
}

int cURLCamera::Capture( Image &image )
{
	bool frameComplete = false;
	uint8_t* directbuffer;

	/* MODE_STREAM specific variables */
	bool SubHeadersParsingComplete = false;
	unsigned int frame_content_length = 0;
	std::string frame_content_type;
	bool need_more_data = false;

	/* Request a writeable buffer of the target image */
	directbuffer = image.WriteBuffer(width, height, colours, subpixelorder);
	if(directbuffer == NULL) {
		Error("Failed requesting writeable buffer for the captured image");
		return (-1);
	}

	/* Grab the mutex to ensure exclusive access to the shared data */
	lock();

	while (!frameComplete) {

		/* If the work thread did a reset, reset our local variables */
		if(bReset) {
			SubHeadersParsingComplete = false;
			frame_content_length = 0;
			frame_content_type.clear();
			need_more_data = false;
			bReset = false;
		}

		if(mode == MODE_UNSET) {
			/* Don't have a mode yet. Sleep while waiting for data */
			nRet = pthread_cond_wait(&data_available_cond,&shareddata_mutex);
			if(nRet != 0) {
				Error("Failed waiting for available data condition variable: %s",strerror(nRet));
				return -20;
			}
		}

		if(mode == MODE_STREAM) {

			/* Subheader parsing */
			while(!SubHeadersParsingComplete && !need_more_data) {

				size_t crlf_start, crlf_end, crlf_size;
				std::string subheader;

				/* Check if the buffer contains something */
				if(databuffer.empty()) {
					/* Empty buffer, wait for data */
					need_more_data = true;
					break;
				}
		 
				/* Find crlf start */
				crlf_start = memcspn(databuffer,"\r\n",databuffer.size());
				if(crlf_start == databuffer.size()) {
					/* Not found, wait for more data */
					need_more_data = true;
					break;
				}

				/* See if we have enough data for determining crlf length */
				if(databuffer.size() < crlf_start+5) {
					/* Need more data */
					need_more_data = true;
					break;
				}

				/* Find crlf end and calculate crlf size */
				crlf_end = memspn(((const char*)databuffer.head())+crlf_start,"\r\n",5);
				crlf_size = (crlf_start + crlf_end) - crlf_start;

				/* Is this the end of a previous stream? (This is just before the boundary) */
				if(crlf_start == 0) {
					databuffer.consume(crlf_size);
					continue;				
				}

				/* Check for invalid CRLF size */
				if(crlf_size > 4) {
					Error("Invalid CRLF length");
				}

				/* Check if the crlf is \n\n or \r\n\r\n (marks end of headers, this is the last header) */
				if( (crlf_size == 2 && memcmp(((const char*)databuffer.head())+crlf_start,"\n\n",2) == 0) || (crlf_size == 4 && memcmp(((const char*)databuffer.head())+crlf_start,"\r\n\r\n",4) == 0) ) {
					/* This is the last header */
					SubHeadersParsingComplete = true;
				}

				/* Copy the subheader, excluding the crlf */
				subheader.assign(databuffer, crlf_start);

				/* Advance the buffer past this one */
				databuffer.consume(crlf_start+crlf_size);

				Debug(7,"Got subheader: %s",subheader.c_str());

				/* Find where the data in this header starts */
				size_t subheader_data_start = subheader.rfind(' ');
				if(subheader_data_start == std::string::npos) {
					subheader_data_start = subheader.find(':');
				}

				/* Extract the data into a string */
				std::string subheader_data = subheader.substr(subheader_data_start+1, std::string::npos);

				Debug(8,"Got subheader data: %s",subheader_data.c_str());

				/* Check the header */
				if(subheader.compare(0,content_length_match_len,content_length_match,content_length_match_len) == 0) {
					/* Found the content-length header */
					frame_content_length = atoi(subheader_data.c_str());
					Debug(6,"Got content-length subheader: %d",frame_content_length);
				} else if(subheader.compare(0,content_type_match_len,content_type_match,content_type_match_len) == 0) {
					/* Found the content-type header */
					frame_content_type = subheader_data;
					Debug(6,"Got content-type subheader: %s",frame_content_type.c_str());
				}

			}

			/* Attempt to extract the frame */
			if(!need_more_data) {
				if(!SubHeadersParsingComplete) {
					/* We haven't parsed all headers yet */
					need_more_data = true;
				} else if(frame_content_length <= 0) {
					/* Invalid frame */
					Error("Invalid frame: invalid content length");
				} else if(frame_content_type != "image/jpeg") {
					/* Unsupported frame type */
					Error("Unsupported frame: %s",frame_content_type.c_str());
				} else if(frame_content_length > databuffer.size()) {
					/* Incomplete frame, wait for more data */
					need_more_data = true;
				} else {
					/* All good. decode the image */
					image.DecodeJpeg(databuffer.extract(frame_content_length), frame_content_length, colours, subpixelorder);
					frameComplete = true;
				}
			}

			/* Attempt to get more data */
			if(need_more_data) {
				nRet = pthread_cond_wait(&data_available_cond,&shareddata_mutex);
				if(nRet != 0) {
					Error("Failed waiting for available data condition variable: %s",strerror(nRet));
					return -18;
				}
				need_more_data = false;
			}

		} else if(mode == MODE_SINGLE) { 
			/* Check if we have anything */
			if (!single_offsets.empty()) {
				if( (single_offsets.front() > 0) && (databuffer.size() >= single_offsets.front()) ) {
					/* Extract frame */
					image.DecodeJpeg(databuffer.extract(single_offsets.front()), single_offsets.front(), colours, subpixelorder);
					single_offsets.pop_front();
					frameComplete = true;
				} else {
					/* This shouldn't happen */
					Error("Internal error. Attempting recovery");
					databuffer.consume(single_offsets.front());
					single_offsets.pop_front();
				}
			} else {
				/* Don't have a frame yet, wait for the request complete condition variable */
				nRet = pthread_cond_wait(&request_complete_cond,&shareddata_mutex);
				if(nRet != 0) {
					Error("Failed waiting for request complete condition variable: %s",strerror(nRet));
					return -19;
				}
			}
		} else {
			/* Failed to match content-type */
			Fatal("Unable to match Content-Type. Check URL, username and password");
		} /* mode */

	} /* frameComplete loop */

	/* Release the mutex */
	unlock();

	if(!frameComplete)
		return -1;

	return 0;
}

int cURLCamera::PostCapture()
{
    // Nothing to do here
    return( 0 );
}

size_t cURLCamera::data_callback(void *buffer, size_t size, size_t nmemb, void *userdata)
{
	lock();

	/* Append the data we just received to our buffer */
	databuffer.append((const char*)buffer, size*nmemb);

	/* Signal data available */
	nRet = pthread_cond_signal(&data_available_cond);
	if(nRet != 0) {
		Error("Failed signaling data available condition variable: %s",strerror(nRet));
		return -16;
	}

	unlock();

	/* Return bytes processed */
	return size*nmemb;
}



size_t cURLCamera::header_callback( void *buffer, size_t size, size_t nmemb, void *userdata)
{
	std::string header;
	header.assign((const char*)buffer, size*nmemb);
	
	Debug(4,"Got header: %s",header.c_str());

	/* Check Content-Type header */	
	if(strncasecmp(header.c_str(),content_type_match,content_type_match_len) == 0) {		
		size_t pos = header.find(';');
		if(pos != std::string::npos) {
			header.erase(pos, std::string::npos);
		}

		pos = header.rfind(' ');
		if(pos == std::string::npos) {
			pos = header.find(':');
		}

		std::string content_type = header.substr(pos+1, std::string::npos);
		Debug(6,"Content-Type is: %s",content_type.c_str());

		lock();

		const char* multipart_match = "multipart/x-mixed-replace";
		const char* image_jpeg_match = "image/jpeg";
		if(content_type.compare(0, strlen(multipart_match), multipart_match) == 0) {
			Debug(7,"Content type matched as multipart/x-mixed-replace");
			mode = MODE_STREAM;
		} else if(content_type.compare(0, strlen(image_jpeg_match), image_jpeg_match) == 0) {
			Debug(7,"Content type matched as image/jpeg");
			mode = MODE_SINGLE;
		}

		unlock();
	}
	
	/* Return bytes processed */
	return size*nmemb;
}

void* cURLCamera::thread_func()
{
	int tRet;
	double dSize;

	c = curl_easy_init();
	if(c == NULL) {
		Fatal("Failed getting easy handle from libcurl");
	}

	/* Set URL */
	cRet = curl_easy_setopt(c, CURLOPT_URL, mPath.c_str());
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl URL: %s", curl_easy_strerror(cRet));
	
	/* Header callback */
	cRet = curl_easy_setopt(c, CURLOPT_HEADERFUNCTION, &header_callback_dispatcher);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl header callback function: %s", curl_easy_strerror(cRet));
	cRet = curl_easy_setopt(c, CURLOPT_HEADERDATA, this);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl header callback object: %s", curl_easy_strerror(cRet));

	/* Data callback */
	cRet = curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, &data_callback_dispatcher);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl data callback function: %s", curl_easy_strerror(cRet));
	cRet = curl_easy_setopt(c, CURLOPT_WRITEDATA, this);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl data callback object: %s", curl_easy_strerror(cRet));

	/* Progress callback */
	cRet = curl_easy_setopt(c, CURLOPT_NOPROGRESS, 0);
	if(cRet != CURLE_OK)
		Fatal("Failed enabling libcurl progress callback function: %s", curl_easy_strerror(cRet));	
	cRet = curl_easy_setopt(c, CURLOPT_PROGRESSFUNCTION, &progress_callback_dispatcher);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl progress callback function: %s", curl_easy_strerror(cRet));
	cRet = curl_easy_setopt(c, CURLOPT_PROGRESSDATA, this);
	if(cRet != CURLE_OK)
		Fatal("Failed setting libcurl progress callback object: %s", curl_easy_strerror(cRet));

	/* Set username and password */
	if(!mUser.empty()) {
		cRet = curl_easy_setopt(c, CURLOPT_USERNAME, mUser.c_str());
		if(cRet != CURLE_OK)
			Error("Failed setting username: %s", curl_easy_strerror(cRet));
	}
	if(!mPass.empty()) {
		cRet = curl_easy_setopt(c, CURLOPT_PASSWORD, mPass.c_str());
		if(cRet != CURLE_OK)
			Error("Failed setting password: %s", curl_easy_strerror(cRet));
	}

	/* Authenication preference */
	cRet = curl_easy_setopt(c, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
	if(cRet != CURLE_OK)
		Warning("Failed setting libcurl acceptable http authenication methods: %s", curl_easy_strerror(cRet));


	/* Work loop */
	for(int attempt=1;attempt<=CURL_MAXRETRY;attempt++) {
		tRet = 0;
		while(!bTerminate) {
			/* Do the work */
			cRet = curl_easy_perform(c);

			if(mode == MODE_SINGLE) {
				if(cRet != CURLE_OK) {
					break;
				}
				/* Attempt to get the size of the file */
				cRet = curl_easy_getinfo(c, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &dSize);
				if(cRet != CURLE_OK) {
					break;
				}
				/* We need to lock for the offsets array and the condition variable */
				lock();
				/* Push the size into our offsets array */
				if(dSize > 0) {
					single_offsets.push_back(dSize);
				} else {
					Fatal("Unable to get the size of the image");
				}
				/* Signal the request complete condition variable */
				tRet = pthread_cond_signal(&request_complete_cond);
				if(tRet != 0) {
					Error("Failed signaling request completed condition variable: %s",strerror(tRet));
				}
				/* Unlock */
				unlock();

			} else if (mode == MODE_STREAM) {
				break;
			}
		}

		/* Return value checking */
		if(cRet == CURLE_ABORTED_BY_CALLBACK || bTerminate) {
			/* Aborted */
			break;
		} else if (cRet != CURLE_OK) {
			/* Some error */
			Error("cURL Request failed: %s",curl_easy_strerror(cRet));
			if(attempt < CURL_MAXRETRY) {
				Error("Retrying.. Attempt %d of %d",attempt,CURL_MAXRETRY);
				/* Do a reset */
				lock();
				databuffer.clear();
				single_offsets.clear();
				mode = MODE_UNSET;
				bReset = true;
				unlock();
			}
			tRet = -50;
		}
	}
			
	/* Cleanup */
	curl_easy_cleanup(c);
	c = NULL;
	
	return (void*)tRet;
}

int cURLCamera::lock() {
	int nRet;

	/* Lock shared data */
	nRet = pthread_mutex_lock(&shareddata_mutex);
	if(nRet != 0) {
		Error("Failed locking shared data mutex: %s",strerror(nRet));
	}
	return nRet;
}

int cURLCamera::unlock() {
	int nRet;

	/* Unlock shared data */
	nRet = pthread_mutex_unlock(&shareddata_mutex);
	if(nRet != 0) {
		Error("Failed unlocking shared data mutex: %s",strerror(nRet));
	}
	return nRet;
}

int cURLCamera::progress_callback(void *userdata, double dltotal, double dlnow, double ultotal, double ulnow)
{
	/* Signal the curl thread to terminate */
	if(bTerminate)
		return -10;
	
	return 0;
}

/* These functions call the functions in the class for the correct object */
size_t data_callback_dispatcher(void *buffer, size_t size, size_t nmemb, void *userdata)
{
	return ((cURLCamera*)userdata)->data_callback(buffer,size,nmemb,userdata);
}

size_t header_callback_dispatcher(void *buffer, size_t size, size_t nmemb, void *userdata)
{
	return ((cURLCamera*)userdata)->header_callback(buffer,size,nmemb,userdata);
}

int progress_callback_dispatcher(void *userdata, double dltotal, double dlnow, double ultotal, double ulnow)
{
	return ((cURLCamera*)userdata)->progress_callback(userdata,dltotal,dlnow,ultotal,ulnow);
}

void* thread_func_dispatcher(void* object) {
	return ((cURLCamera*)object)->thread_func();
}



#endif // HAVE_LIBCURL