add point logging for screenshots

[numtypysics.git] / happyhttp.cpp

/*
 * HappyHTTP - a simple HTTP library
 * Version 0.1
 * 
 * Copyright (c) 2006 Ben Campbell
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * 
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software in a
 * product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 *
 * 2. Altered source versions must be plainly marked as such, and must not
 * be misrepresented as being the original software.
 * 
 * 3. This notice may not be removed or altered from any source distribution.
 *
 */


#include "happyhttp.h"

#ifndef WIN32
//      #include <sys/types.h>
        #include <sys/socket.h>
        #include <netinet/in.h>
        #include <arpa/inet.h>
        #include <netdb.h>      // for gethostbyname()
        #include <errno.h>
#endif

#ifdef WIN32
        #include <winsock2.h>
        #define vsnprintf _vsnprintf
#endif

#include <cstdio>
#include <cstring>
#include <cstdarg>
#include <assert.h>

#include <string>
#include <vector>
#include <string>
#include <algorithm>




using namespace std;


namespace happyhttp
{

#ifdef WIN32
const char* GetWinsockErrorString( int err );
#endif


//---------------------------------------------------------------------
// Helper functions
//---------------------------------------------------------------------



void BailOnSocketError( const char* context )
{
#ifdef WIN32

        int e = WSAGetLastError();
        const char* msg = GetWinsockErrorString( e );
#else
        const char* msg = strerror( errno );
#endif
        throw Wobbly( "%s: %s", context, msg );
}


#ifdef WIN32

const char* GetWinsockErrorString( int err )
{
        switch( err)
        {
        case 0:                                 return "No error";
    case WSAEINTR:                      return "Interrupted system call";
    case WSAEBADF:                      return "Bad file number";
    case WSAEACCES:                     return "Permission denied";
    case WSAEFAULT:                     return "Bad address";
    case WSAEINVAL:                     return "Invalid argument";
    case WSAEMFILE:                     return "Too many open sockets";
    case WSAEWOULDBLOCK:        return "Operation would block";
    case WSAEINPROGRESS:        return "Operation now in progress";
    case WSAEALREADY:           return "Operation already in progress";
    case WSAENOTSOCK:           return "Socket operation on non-socket";
    case WSAEDESTADDRREQ:       return "Destination address required";
    case WSAEMSGSIZE:           return "Message too long";
    case WSAEPROTOTYPE:         return "Protocol wrong type for socket";
    case WSAENOPROTOOPT:        return "Bad protocol option";
        case WSAEPROTONOSUPPORT:        return "Protocol not supported";
        case WSAESOCKTNOSUPPORT:        return "Socket type not supported";
    case WSAEOPNOTSUPP:         return "Operation not supported on socket";
    case WSAEPFNOSUPPORT:       return "Protocol family not supported";
    case WSAEAFNOSUPPORT:       return "Address family not supported";
    case WSAEADDRINUSE:         return "Address already in use";
    case WSAEADDRNOTAVAIL:      return "Can't assign requested address";
    case WSAENETDOWN:           return "Network is down";
    case WSAENETUNREACH:        return "Network is unreachable";
    case WSAENETRESET:          return "Net connection reset";
    case WSAECONNABORTED:       return "Software caused connection abort";
    case WSAECONNRESET:         return "Connection reset by peer";
    case WSAENOBUFS:            return "No buffer space available";
    case WSAEISCONN:            return "Socket is already connected";
    case WSAENOTCONN:           return "Socket is not connected";
    case WSAESHUTDOWN:          return "Can't send after socket shutdown";
    case WSAETOOMANYREFS:       return "Too many references, can't splice";
    case WSAETIMEDOUT:          return "Connection timed out";
    case WSAECONNREFUSED:       return "Connection refused";
    case WSAELOOP:                      return "Too many levels of symbolic links";
    case WSAENAMETOOLONG:       return "File name too long";
    case WSAEHOSTDOWN:          return "Host is down";
    case WSAEHOSTUNREACH:       return "No route to host";
    case WSAENOTEMPTY:          return "Directory not empty";
    case WSAEPROCLIM:           return "Too many processes";
    case WSAEUSERS:                     return "Too many users";
    case WSAEDQUOT:                     return "Disc quota exceeded";
    case WSAESTALE:                     return "Stale NFS file handle";
    case WSAEREMOTE:            return "Too many levels of remote in path";
        case WSASYSNOTREADY:    return "Network system is unavailable";
        case WSAVERNOTSUPPORTED:        return "Winsock version out of range";
    case WSANOTINITIALISED:     return "WSAStartup not yet called";
    case WSAEDISCON:            return "Graceful shutdown in progress";
    case WSAHOST_NOT_FOUND:     return "Host not found";
    case WSANO_DATA:            return "No host data of that type was found";
        }

        return "unknown";
};

#endif // WIN32


// return true if socket has data waiting to be read
bool datawaiting( int sock )
{
        fd_set fds;
        FD_ZERO( &fds );
        FD_SET( sock, &fds );

        struct timeval tv;
        tv.tv_sec = 0;
        tv.tv_usec = 0;

        int r = select( sock+1, &fds, NULL, NULL, &tv);
        if (r < 0)
                BailOnSocketError( "select" );

        if( FD_ISSET( sock, &fds ) )
                return true;
        else
                return false;
}


// Try to work out address from string
// returns 0 if bad
struct in_addr *atoaddr( const char* address)
{
        struct hostent *host;
        static struct in_addr saddr;

        // First try nnn.nnn.nnn.nnn form
        saddr.s_addr = inet_addr(address);
        if (saddr.s_addr != -1)
                return &saddr;

        host = gethostbyname(address);
        if( host )
                return (struct in_addr *) *host->h_addr_list;

        return 0;
}







//---------------------------------------------------------------------
//
// Exception class
//
//---------------------------------------------------------------------


Wobbly::Wobbly( const char* fmt, ... )
{
        va_list ap;
        va_start( ap,fmt);
        int n = vsnprintf( m_Message, MAXLEN, fmt, ap );
        va_end( ap );
        if(n==MAXLEN)
                m_Message[MAXLEN-1] = '\0';
}








//---------------------------------------------------------------------
//
// Connection
//
//---------------------------------------------------------------------
Connection::Connection( const char* host, int port ) :
        m_ResponseBeginCB(0),
        m_ResponseDataCB(0),
        m_ResponseCompleteCB(0),
        m_UserData(0),
        m_State( IDLE ),
        m_Host( host ),
        m_Port( port ),
        m_Sock(-1)
{
}


void Connection::setcallbacks(
        ResponseBegin_CB begincb,
        ResponseData_CB datacb,
        ResponseComplete_CB completecb,
        void* userdata )
{
        m_ResponseBeginCB = begincb;
        m_ResponseDataCB = datacb;
        m_ResponseCompleteCB = completecb;
        m_UserData = userdata;
}


void Connection::connect()
{
        in_addr* addr = atoaddr( m_Host.c_str() );
        if( !addr )
                throw Wobbly( "Invalid network address" );

        sockaddr_in address;
        memset( (char*)&address, 0, sizeof(address) );
        address.sin_family = AF_INET;
        address.sin_port = htons( m_Port );
        address.sin_addr.s_addr = addr->s_addr;

        m_Sock = socket( AF_INET, SOCK_STREAM, 0 );
        if( m_Sock < 0 )
                BailOnSocketError( "socket()" );

//      printf("Connecting to %s on port %d.\n",inet_ntoa(*addr), port);

        if( ::connect( m_Sock, (sockaddr const*)&address, sizeof(address) ) < 0 )
                BailOnSocketError( "connect()" );
}


void Connection::close()
{
#ifdef WIN32
        if( m_Sock >= 0 )
                ::closesocket( m_Sock );
#else
        if( m_Sock >= 0 )
                ::close( m_Sock );
#endif
        m_Sock = -1;

        // discard any incomplete responses
        while( !m_Outstanding.empty() )
        {
                delete m_Outstanding.front();
                m_Outstanding.pop_front();
        }
}


Connection::~Connection()
{
        close();
}

void Connection::request( const char* method,
        const char* url,
        const char* headers[],
        const unsigned char* body,
        int bodysize )
{

        bool gotcontentlength = false;  // already in headers?

        // check headers for content-length
        // TODO: check for "Host" and "Accept-Encoding" too
        // and avoid adding them ourselves in putrequest()
        if( headers )
        {
                const char** h = headers;
                while( *h )
                {
                        const char* name = *h++;
                        const char* value = *h++;
                        assert( value != 0 );   // name with no value!

                        if( 0==strcasecmp( name, "content-length" ) )
                                gotcontentlength = true;
                }
        }

        putrequest( method, url );

        if( body && !gotcontentlength )
                putheader( "Content-Length", bodysize );

        if( headers )
        {
                const char** h = headers;
                while( *h )
                {
                        const char* name = *h++;
                        const char* value = *h++;
                        putheader( name, value );
                }
        }
        endheaders();

        if( body )
                send( body, bodysize );

}




void Connection::putrequest( const char* method, const char* url )
{
        if( m_State != IDLE )
                throw Wobbly( "Request already issued" );

        m_State = REQ_STARTED;

        char req[ 512 ];
        sprintf( req, "%s %s HTTP/1.1", method, url );
        m_Buffer.push_back( req );

        putheader( "Host", m_Host.c_str() );    // required for HTTP1.1

        // don't want any fancy encodings please
        putheader("Accept-Encoding", "identity");

        // Push a new response onto the queue
        Response *r = new Response( method, *this );
        m_Outstanding.push_back( r );
}


void Connection::putheader( const char* header, const char* value )
{
        if( m_State != REQ_STARTED )
                throw Wobbly( "putheader() failed" );
        m_Buffer.push_back( string(header) + ": " + string( value ) );
}

void Connection::putheader( const char* header, int numericvalue )
{
        char buf[32];
        sprintf( buf, "%d", numericvalue );
        putheader( header, buf );
}

void Connection::endheaders()
{
        if( m_State != REQ_STARTED )
                throw Wobbly( "Cannot send header" );
        m_State = IDLE;

        m_Buffer.push_back( "" );

        string msg;
        vector< string>::const_iterator it;
        for( it = m_Buffer.begin(); it != m_Buffer.end(); ++it )
                msg += (*it) + "\r\n";

        m_Buffer.clear();

//      printf( "%s", msg.c_str() );
        send( (const unsigned char*)msg.c_str(), msg.size() );
}



void Connection::send( const unsigned char* buf, int numbytes )
{
//      fwrite( buf, 1,numbytes, stdout );
        
        if( m_Sock < 0 )
                connect();

        while( numbytes > 0 )
        {
#ifdef WIN32
                int n = ::send( m_Sock, (const char*)buf, numbytes, 0 );
#else
                int n = ::send( m_Sock, buf, numbytes, 0 );
#endif
                if( n<0 )
                        BailOnSocketError( "send()" );
                numbytes -= n;
                buf += n;
        }
}


void Connection::pump()
{
        if( m_Outstanding.empty() )
                return;         // no requests outstanding

        assert( m_Sock >0 );    // outstanding requests but no connection!

        if( !datawaiting( m_Sock ) )
                return;                         // recv will block

        unsigned char buf[ 2048 ];
        int a = recv( m_Sock, (char*)buf, sizeof(buf), 0 );
        if( a<0 )
                BailOnSocketError( "recv()" );

        if( a== 0 )
        {
                // connection has closed

                Response* r = m_Outstanding.front();
                r->notifyconnectionclosed();
                assert( r->completed() );
                delete r;
                m_Outstanding.pop_front();

                // any outstanding requests will be discarded
                close();
        }
        else
        {
                int used = 0;
                while( used < a && !m_Outstanding.empty() )
                {

                        Response* r = m_Outstanding.front();
                        int u = r->pump( &buf[used], a-used );

                        // delete response once completed
                        if( r->completed() )
                        {
                                delete r;
                                m_Outstanding.pop_front();
                        }
                        used += u;
                }

                // NOTE: will lose bytes if response queue goes empty
                // (but server shouldn't be sending anything if we don't have
                // anything outstanding anyway)
                assert( used == a );    // all bytes should be used up by here.
        }
}






//---------------------------------------------------------------------
//
// Response
//
//---------------------------------------------------------------------


Response::Response( const char* method, Connection& conn ) :
        m_Connection( conn ),
        m_State( STATUSLINE ),
        m_Method( method ),
        m_Version( 0 ),
        m_Status(0),
        m_BytesRead(0),
        m_Chunked(false),
        m_ChunkLeft(0),
        m_Length(-1),
        m_WillClose(false)
{
}


const char* Response::getheader( const char* name ) const
{
        std::string lname( name );
        std::transform( lname.begin(), lname.end(), lname.begin(), (int(*)(int))tolower );

        std::map< std::string, std::string >::const_iterator it = m_Headers.find( lname );
        if( it == m_Headers.end() )
                return 0;
        else
                return it->second.c_str();
}


int Response::getstatus() const
{
        // only valid once we've got the statusline
        assert( m_State != STATUSLINE );
        return m_Status;
}


const char* Response::getreason() const
{
        // only valid once we've got the statusline
        assert( m_State != STATUSLINE );
        return m_Reason.c_str();
}



// Connection has closed
void Response::notifyconnectionclosed()
{
        if( m_State == COMPLETE )
                return;

        // eof can be valid...
        if( m_State == BODY &&
                !m_Chunked &&
                m_Length == -1 )
        {
                Finish();       // we're all done!
        }
        else
        {
                throw Wobbly( "Connection closed unexpectedly" );
        }
}



int Response::pump( const unsigned char* data, int datasize )
{
        assert( datasize != 0 );
        int count = datasize;

        while( count > 0 && m_State != COMPLETE )
        {
                if( m_State == STATUSLINE ||
                        m_State == HEADERS ||
                        m_State == TRAILERS ||
                        m_State == CHUNKLEN ||
                        m_State == CHUNKEND )
                {
                        // we want to accumulate a line
                        while( count > 0 )
                        {
                                char c = (char)*data++;
                                --count;
                                if( c == '\n' )
                                {
                                        // now got a whole line!
                                        switch( m_State )
                                        {
                                                case STATUSLINE:
                                                        ProcessStatusLine( m_LineBuf );
                                                        break;
                                                case HEADERS:
                                                        ProcessHeaderLine( m_LineBuf );
                                                        break;
                                                case TRAILERS:
                                                        ProcessTrailerLine( m_LineBuf );
                                                        break;
                                                case CHUNKLEN:
                                                        ProcessChunkLenLine( m_LineBuf );
                                                        break;
                                                case CHUNKEND:
                                                        // just soak up the crlf after body and go to next state
                                                        assert( m_Chunked == true );
                                                        m_State = CHUNKLEN;
                                                        break;
                                                default:
                                                        break;
                                        }
                                        m_LineBuf.clear();
                                        break;          // break out of line accumulation!
                                }
                                else
                                {
                                        if( c != '\r' )         // just ignore CR
                                                m_LineBuf += c;
                                }
                        }
                }
                else if( m_State == BODY )
                {
                        int bytesused = 0;
                        if( m_Chunked )
                                bytesused = ProcessDataChunked( data, count );
                        else
                                bytesused = ProcessDataNonChunked( data, count );
                        data += bytesused;
                        count -= bytesused;
                }
        }

        // return number of bytes used
        return datasize - count;
}



void Response::ProcessChunkLenLine( std::string const& line )
{
        // chunklen in hex at beginning of line
        m_ChunkLeft = strtol( line.c_str(), NULL, 16 );
        
        if( m_ChunkLeft == 0 )
        {
                // got the whole body, now check for trailing headers
                m_State = TRAILERS;
                m_HeaderAccum.clear();
        }
        else
        {
                m_State = BODY;
        }
}


// handle some body data in chunked mode
// returns number of bytes used.
int Response::ProcessDataChunked( const unsigned char* data, int count )
{
        assert( m_Chunked );

        int n = count;
        if( n>m_ChunkLeft )
                n = m_ChunkLeft;

        // invoke callback to pass out the data
        if( m_Connection.m_ResponseDataCB )
                (m_Connection.m_ResponseDataCB)( this, m_Connection.m_UserData, data, n );

        m_BytesRead += n;

        m_ChunkLeft -= n;
        assert( m_ChunkLeft >= 0);
        if( m_ChunkLeft == 0 )
        {
                // chunk completed! now soak up the trailing CRLF before next chunk
                m_State = CHUNKEND;
        }
        return n;
}

// handle some body data in non-chunked mode.
// returns number of bytes used.
int Response::ProcessDataNonChunked( const unsigned char* data, int count )
{
        int n = count;
        if( m_Length != -1 )
        {
                // we know how many bytes to expect
                int remaining = m_Length - m_BytesRead;
                if( n > remaining )
                        n = remaining;
        }

        // invoke callback to pass out the data
        if( m_Connection.m_ResponseDataCB )
                (m_Connection.m_ResponseDataCB)( this, m_Connection.m_UserData, data, n );

        m_BytesRead += n;

        // Finish if we know we're done. Else we're waiting for connection close.
        if( m_Length != -1 && m_BytesRead == m_Length )
                Finish();

        return n;
}


void Response::Finish()
{
        m_State = COMPLETE;

        // invoke the callback
        if( m_Connection.m_ResponseCompleteCB )
                (m_Connection.m_ResponseCompleteCB)( this, m_Connection.m_UserData );
}


void Response::ProcessStatusLine( std::string const& line )
{
        const char* p = line.c_str();

        // skip any leading space
        while( *p && *p == ' ' )
                ++p;

        // get version
        while( *p && *p != ' ' )
                m_VersionString += *p++;
        while( *p && *p == ' ' )
                ++p;

        // get status code
        std::string status;
        while( *p && *p != ' ' )
                status += *p++;
        while( *p && *p == ' ' )
                ++p;

        // rest of line is reason
        while( *p )
                m_Reason += *p++;

        m_Status = atoi( status.c_str() );
        if( m_Status < 100 || m_Status > 999 )
                throw Wobbly( "BadStatusLine (%s)", line.c_str() );

/*
        printf( "version: '%s'\n", m_VersionString.c_str() );
        printf( "status: '%d'\n", m_Status );
        printf( "reason: '%s'\n", m_Reason.c_str() );
*/

        if( m_VersionString == "HTTP:/1.0" )
                m_Version = 10;
        else if( 0==m_VersionString.compare( 0,7,"HTTP/1." ) )
                m_Version = 11;
        else
                throw Wobbly( "UnknownProtocol (%s)", m_VersionString.c_str() );
        // TODO: support for HTTP/0.9

        
        // OK, now we expect headers!
        m_State = HEADERS;
        m_HeaderAccum.clear();
}


// process accumulated header data
void Response::FlushHeader()
{
        if( m_HeaderAccum.empty() )
                return; // no flushing required

        const char* p = m_HeaderAccum.c_str();

        std::string header;
        std::string value;
        while( *p && *p != ':' )
                header += tolower( *p++ );

        // skip ':'
        if( *p )
                ++p;

        // skip space
        while( *p && (*p ==' ' || *p=='\t') )
                ++p;

        value = p; // rest of line is value

        m_Headers[ header ] = value;
//      printf("header: ['%s': '%s']\n", header.c_str(), value.c_str() );       

        m_HeaderAccum.clear();
}


void Response::ProcessHeaderLine( std::string const& line )
{
        const char* p = line.c_str();
        if( line.empty() )
        {
                FlushHeader();
                // end of headers

                // HTTP code 100 handling (we ignore 'em)
                if( m_Status == CONTINUE )
                        m_State = STATUSLINE;   // reset parsing, expect new status line
                else
                        BeginBody();                    // start on body now!
                return;
        }

        if( isspace(*p) )
        {
                // it's a continuation line - just add it to previous data
                ++p;
                while( *p && isspace( *p ) )
                        ++p;

                m_HeaderAccum += ' ';
                m_HeaderAccum += p;
        }
        else
        {
                // begin a new header
                FlushHeader();
                m_HeaderAccum = p;
        }
}


void Response::ProcessTrailerLine( std::string const& line )
{
        // TODO: handle trailers?
        // (python httplib doesn't seem to!)
        if( line.empty() )
                Finish();

        // just ignore all the trailers...
}



// OK, we've now got all the headers read in, so we're ready to start
// on the body. But we need to see what info we can glean from the headers
// first...
void Response::BeginBody()
{

        m_Chunked = false;
        m_Length = -1;  // unknown
        m_WillClose = false;

        // using chunked encoding?
        const char* trenc = getheader( "transfer-encoding" );
        if( trenc && 0==strcasecmp( trenc, "chunked") )
        {
                m_Chunked = true;
                m_ChunkLeft = -1;       // unknown
        }

        m_WillClose = CheckClose();

        // length supplied?
        const char* contentlen = getheader( "content-length" );
        if( contentlen && !m_Chunked )
        {
                m_Length = atoi( contentlen );
        }

        // check for various cases where we expect zero-length body
        if( m_Status == NO_CONTENT ||
                m_Status == NOT_MODIFIED ||
                ( m_Status >= 100 && m_Status < 200 ) ||                // 1xx codes have no body
                m_Method == "HEAD" )
        {
                m_Length = 0;
        }


        // if we're not using chunked mode, and no length has been specified,
        // assume connection will close at end.
        if( !m_WillClose && !m_Chunked && m_Length == -1 )
                m_WillClose = true;



        // Invoke the user callback, if any
        if( m_Connection.m_ResponseBeginCB )
                (m_Connection.m_ResponseBeginCB)( this, m_Connection.m_UserData );

/*
        printf("---------BeginBody()--------\n");
        printf("Length: %d\n", m_Length );
        printf("WillClose: %d\n", (int)m_WillClose );
        printf("Chunked: %d\n", (int)m_Chunked );
        printf("ChunkLeft: %d\n", (int)m_ChunkLeft );
        printf("----------------------------\n");
*/
        // now start reading body data!
        if( m_Chunked )
                m_State = CHUNKLEN;
        else
                m_State = BODY;
}


// return true if we think server will automatically close connection
bool Response::CheckClose()
{
        if( m_Version == 11 )
        {
                // HTTP1.1
                // the connection stays open unless "connection: close" is specified.
                const char* conn = getheader( "connection" );
                if( conn && 0==strcasecmp( conn, "close" ) )
                        return true;
                else
                        return false;
        }

        // Older HTTP
        // keep-alive header indicates persistant connection 
        if( getheader( "keep-alive" ) )
                return false;

        // TODO: some special case handling for Akamai and netscape maybe?
        // (see _check_close() in python httplib.py for details)

        return true;
}



}       // end namespace happyhttp