// MultipartParser.cpp
// Implements the cMultipartParser class that parses messages in "multipart/*" encoding into the separate parts
#include "Globals.h"
#include "MultipartParser.h"
#include "NameValueParser.h"
// Disable MSVC warnings:
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable:4355) // 'this' : used in base member initializer list
#endif
////////////////////////////////////////////////////////////////////////////////
// self-test:
#if 0
class cMultipartParserTest :
public cMultipartParser::cCallbacks
{
public:
cMultipartParserTest(void)
{
cMultipartParser Parser("multipart/mixed; boundary=\"MyBoundaryString\"; foo=bar", *this);
const char Data[] =
"ThisIsIgnoredPrologue\r\n\
--MyBoundaryString\r\n\
\r\n\
Body with confusing strings\r\n\
--NotABoundary\r\n\
--MyBoundaryStringWithPostfix\r\n\
--\r\n\
--MyBoundaryString\r\n\
content-disposition: inline\r\n\
\r\n\
This is body\r\n\
--MyBoundaryString\r\n\
\r\n\
Headerless body with trailing CRLF\r\n\
\r\n\
--MyBoundaryString--\r\n\
ThisIsIgnoredEpilogue";
printf("Multipart parsing test commencing.\n");
Parser.Parse(Data, sizeof(Data) - 1);
// DEBUG: Check if the onscreen output corresponds with the data above
printf("Multipart parsing test finished\n");
}
virtual void OnPartStart(void) override
{
printf("Starting a new part\n");
}
virtual void OnPartHeader(const AString & a_Key, const AString & a_Value) override
{
printf(" Hdr: \"%s\"=\"%s\"\n", a_Key.c_str(), a_Value.c_str());
}
virtual void OnPartData(const char * a_Data, int a_Size) override
{
printf(" Data: %d bytes, \"%.*s\"\n", a_Size, a_Size, a_Data);
}
virtual void OnPartEnd(void) override
{
printf("Part end\n");
}
} g_Test;
#endif
////////////////////////////////////////////////////////////////////////////////
// cMultipartParser:
cMultipartParser::cMultipartParser(const AString & a_ContentType, cCallbacks & a_Callbacks) :
m_Callbacks(a_Callbacks),
m_IsValid(true),
m_EnvelopeParser(*this),
m_HasHadData(false)
{
// Check that the content type is multipart:
AString ContentType(a_ContentType);
if (strncmp(ContentType.c_str(), "multipart/", 10) != 0)
{
m_IsValid = false;
return;
}
size_t idxSC = ContentType.find(';', 10);
if (idxSC == AString::npos)
{
m_IsValid = false;
return;
}
// Find the multipart boundary:
ContentType.erase(0, idxSC + 1);
cNameValueParser CTParser(ContentType.c_str(), ContentType.size());
CTParser.Finish();
if (!CTParser.IsValid())
{
m_IsValid = false;
return;
}
m_Boundary = CTParser["boundary"];
m_IsValid = !m_Boundary.empty();
if (!m_IsValid)
{
return;
}
// Set the envelope parser for parsing the body, so that our Parse() function parses the ignored prefix data as a body
m_EnvelopeParser.SetIsInHeaders(false);
// Append an initial CRLF to the incoming data, so that a body starting with the boundary line will get caught
m_IncomingData.assign("\r\n");
/*
m_Boundary = AString("\r\n--") + m_Boundary
m_BoundaryEnd = m_Boundary + "--\r\n";
m_Boundary = m_Boundary + "\r\n";
*/
}
void cMultipartParser::Parse(const char * a_Data, size_t a_Size)
{
// Skip parsing if invalid
if (!m_IsValid)
{
return;
}
// Append to buffer, then parse it:
m_IncomingData.append(a_Data, a_Size);
for (;;)
{
if (m_EnvelopeParser.IsInHeaders())
{
size_t BytesConsumed = m_EnvelopeParser.Parse(m_IncomingData.data(), m_IncomingData.size());
if (BytesConsumed == AString::npos)
{
m_IsValid = false;
return;
}
if ((BytesConsumed == a_Size) && m_EnvelopeParser.IsInHeaders())
{
// All the incoming data has been consumed and still waiting for more
return;
}
m_IncomingData.erase(0, BytesConsumed);
}
// Search for boundary / boundary end:
size_t idxBoundary = m_IncomingData.find("\r\n--");
if (idxBoundary == AString::npos)
{
// Boundary string start not present, present as much data to the part callback as possible
if (m_IncomingData.size() > m_Boundary.size() + 8)
{
size_t BytesToReport = m_IncomingData.size() - m_Boundary.size() - 8;
m_Callbacks.OnPartData(m_IncomingData.data(), BytesToReport);
m_IncomingData.erase(0, BytesToReport);
}
return;
}
if (idxBoundary > 0)
{
m_Callbacks.OnPartData(m_IncomingData.data(), idxBoundary);
m_IncomingData.erase(0, idxBoundary);
}
idxBoundary = 4;
size_t LineEnd = m_IncomingData.find("\r\n", idxBoundary);
if (LineEnd == AString::npos)
{
// Not a complete line yet, present as much data to the part callback as possible
if (m_IncomingData.size() > m_Boundary.size() + 8)
{
size_t BytesToReport = m_IncomingData.size() - m_Boundary.size() - 8;
m_Callbacks.OnPartData(m_IncomingData.data(), BytesToReport);
m_IncomingData.erase(0, BytesToReport);
}
return;
}
if (
(LineEnd - idxBoundary != m_Boundary.size()) && // Line length not equal to boundary
(LineEnd - idxBoundary != m_Boundary.size() + 2) // Line length not equal to boundary end
)
{
// Got a line, but it's not a boundary, report it as data:
m_Callbacks.OnPartData(m_IncomingData.data(), LineEnd);
m_IncomingData.erase(0, LineEnd);
continue;
}
if (strncmp(m_IncomingData.c_str() + idxBoundary, m_Boundary.c_str(), m_Boundary.size()) == 0)
{
// Boundary or BoundaryEnd found:
m_Callbacks.OnPartEnd();
size_t idxSlash = idxBoundary + m_Boundary.size();
if ((m_IncomingData[idxSlash] == '-') && (m_IncomingData[idxSlash + 1] == '-'))
{
// This was the last part
m_Callbacks.OnPartData(m_IncomingData.data() + idxSlash + 4, m_IncomingData.size() - idxSlash - 4);
m_IncomingData.clear();
return;
}
m_Callbacks.OnPartStart();
m_IncomingData.erase(0, LineEnd + 2);
// Keep parsing for the headers that may have come with this data:
m_EnvelopeParser.Reset();
continue;
}
// It's a line, but not a boundary. It can be fully sent to the data receiver, since a boundary cannot cross lines
m_Callbacks.OnPartData(m_IncomingData.c_str(), LineEnd);
m_IncomingData.erase(0, LineEnd);
} // while (true)
}
void cMultipartParser::OnHeaderLine(const AString & a_Key, const AString & a_Value)
{
m_Callbacks.OnPartHeader(a_Key, a_Value);
}
