# Crow: /home/farook/cppsrv/crow-0.3-fordoc/include/crow/multipart.h Source File

multipart.h
#pragma once
#include <string>
#include <vector>
#include <sstream>
#include "crow/http_request.h"
#include "crow/returnable.h"
namespace crow
{
///Encapsulates anything related to processing and organizing `multipart/xyz` messages
namespace multipart
{
const std::string dd = "--";
const std::string crlf = "\r\n";
///The first part in a section, contains metadata about the part
struct header
{
std::pair<std::string, std::string> value; ///< The first part of the header, usually `Content-Type` or `Content-Disposition`
std::unordered_map<std::string, std::string> params; ///< The parameters of the header, come after the `value`
};
///One part of the multipart message
///It is usually separated from other sections by a `boundary`
///
struct part
{
std::vector<header> headers; ///< (optional) The first part before the data, Contains information regarding the type of data and encoding
std::string body; ///< The actual data in the part
};
///The parsed multipart request/response
struct message : public returnable
{
ci_map headers;
std::string boundary; ///< The text boundary that separates different `parts`
std::vector<part> parts; ///< The individual parts of the message
const std::string& get_header_value(const std::string& key) const
{
return crow::get_header_value(headers, key);
}
///Represent all parts as a string (**does not include message headers**)
std::string dump() const override
{
std::stringstream str;
std::string delimiter = dd + boundary;
for (unsigned i=0 ; i<parts.size(); i++)
{
str << delimiter << crlf;
str << dump(i);
}
str << delimiter << dd << crlf;
return str.str();
}
///Represent an individual part as a string
std::string dump(int part_) const
{
std::stringstream str;
part item = parts[part_];
for (header item_h: item.headers)
{
str << item_h.value.first << ": " << item_h.value.second;
for (auto& it: item_h.params)
{
str << "; " << it.first << '=' << pad(it.second);
}
str << crlf;
}
str << crlf;
str << item.body << crlf;
return str.str();
}
///Default constructor using default values
message(const ci_map& headers, const std::string& boundary, const std::vector<part>& sections)
: returnable("multipart/form-data"), headers(headers), boundary(boundary), parts(sections){}
///Create a multipart message from a request data
message(const request& req)
: returnable("multipart/form-data"),
headers(req.headers),
boundary(get_boundary(get_header_value("Content-Type"))),
parts(parse_body(req.body))
{}
private:
std::string get_boundary(const std::string& header) const
{
size_t found = header.find("boundary=");
if (found)
return header.substr(found+9);
return std::string();
}
std::vector<part> parse_body(std::string body)
{
std::vector<part> sections;
std::string delimiter = dd + boundary;
while(body != (crlf))
{
size_t found = body.find(delimiter);
std::string section = body.substr(0, found);
//+2 is the CRLF
//We don't check it and delete it so that the same delimiter can be used for
//the last delimiter (--delimiter--CRLF).
body.erase(0, found + delimiter.length() + 2);
if (!section.empty())
{
sections.emplace_back(parse_section(section));
}
}
return sections;
}
part parse_section(std::string& section)
{
struct part to_return;
size_t found = section.find(crlf+crlf);
std::string head_line = section.substr(0, found+2);
section.erase(0, found + 4);
parse_section_head(head_line, to_return);
to_return.body = section.substr(0, section.length()-2);
return to_return;
}
void parse_section_head(std::string& lines, part& part)
{
while (!lines.empty())
{
header to_add;
size_t found = lines.find(crlf);
std::string line = lines.substr(0, found);
lines.erase(0, found+2);
//add the header if available
if (!line.empty())
{
size_t found = line.find("; ");
std::string header = line.substr(0, found);
if (found != std::string::npos)
line.erase(0, found+2);
else
line = std::string();
size_t header_split = header.find(": ");
to_add.value = std::pair<std::string, std::string>(header.substr(0, header_split), header.substr(header_split+2));
}
//add the parameters
while (!line.empty())
{
size_t found = line.find("; ");
std::string param = line.substr(0, found);
if (found != std::string::npos)
line.erase(0, found+2);
else
line = std::string();
size_t param_split = param.find('=');
std::string value = param.substr(param_split+1);
to_add.params.emplace(param.substr(0, param_split), trim(value));
}
part.headers.emplace_back(to_add);
}
}
inline std::string trim (std::string& string, const char& excess = '"') const
{
if (string.length() > 1 && string[0] == excess && string[string.length()-1] == excess)
return string.substr(1, string.length()-2);
return string;
}
inline std::string pad (std::string& string, const char& padding = '"') const
{
return (padding + string + padding);
}
};
}
}
crow::multipart::header
The first part in a section, contains metadata about the part.
Definition: multipart.h:20
crow::multipart::header::params
std::unordered_map< std::string, std::string > params
The parameters of the header, come after the value
Definition: multipart.h:22
crow::multipart::header::value
std::pair< std::string, std::string > value
The first part of the header, usually Content-Type or Content-Disposition
Definition: multipart.h:21
crow::multipart::message
The parsed multipart request/response.
Definition: multipart.h:37
crow::multipart::message::message
message(const ci_map &headers, const std::string &boundary, const std::vector< part > &sections)
Default constructor using default values.
Definition: multipart.h:82
crow::multipart::message::parts
std::vector< part > parts
The individual parts of the message.
Definition: multipart.h:40
crow::multipart::message::message
message(const request &req)
Create a multipart message from a request data.
Definition: multipart.h:86
crow::multipart::message::boundary
std::string boundary
The text boundary that separates different parts
Definition: multipart.h:39
crow::multipart::message::dump
std::string dump(int part_) const
Represent an individual part as a string.
Definition: multipart.h:63
crow::multipart::message::dump
std::string dump() const override
Represent all parts as a string (does not include message headers)
Definition: multipart.h:48
crow::multipart::part
One part of the multipart message.
Definition: multipart.h:30
crow::multipart::part::body
std::string body
The actual data in the part.
Definition: multipart.h:32
crow::multipart::part::headers
std::vector< header > headers
(optional) The first part before the data, Contains information regarding the type of data and encodi...
Definition: multipart.h:31
crow::request
An HTTP request.
Definition: http_request.h:27
crow::returnable
An abstract class that allows any other class to be returned by a handler.
Definition: returnable.h:9