i2pdtunnelwizard/http/crow/multipart_view.h

313 lines
12 KiB
C++

#pragma once
#include <charconv>
#include <string>
#include <vector>
#include <string_view>
#include <sstream>
#include "http_request.h"
// for crow::multipart::dd
#include "multipart.h"
#include "ci_map.h"
namespace crow
{
/// Encapsulates anything related to processing and organizing `multipart/xyz` messages
namespace multipart
{
/// The first part in a section, contains metadata about the part
struct header_view
{
std::string_view value; ///< The first part of the header, usually `Content-Type` or `Content-Disposition`
std::unordered_map<std::string_view, std::string_view> params; ///< The parameters of the header, come after the `value`
/// Returns \ref value as integer
operator int() const
{
int result = 0;
std::from_chars(value.data(), value.data() + value.size(), result);
return result;
}
/// Returns \ref value as double
operator double() const
{
// There's no std::from_chars for floating-point types in a lot of STLs
return std::stod(static_cast<std::string>(value));
}
};
/// Multipart header map (key is header key).
using mph_view_map = std::unordered_multimap<std::string_view, header_view, ci_hash, ci_key_eq>;
/// Finds and returns the header with the specified key. (returns an empty header if nothing is found)
inline const header_view& get_header_object(const mph_view_map& headers, const std::string_view key)
{
const auto header = headers.find(key);
if (header != headers.cend())
{
return header->second;
}
static header_view empty;
return empty;
}
/// String padded with the specified padding (double quotes by default)
struct padded
{
std::string_view value; ///< String to pad
const char padding = '"'; ///< Padding to use
/// Outputs padded value to the stream
friend std::ostream& operator<<(std::ostream& stream, const padded value_)
{
return stream << value_.padding << value_.value << value_.padding;
}
};
///One part of the multipart message
///
/// It is usually separated from other sections by a `boundary`
struct part_view
{
mph_view_map headers; ///< (optional) The first part before the data, Contains information regarding the type of data and encoding
std::string_view body; ///< The actual data in the part
/// Returns \ref body as integer
operator int() const
{
int result = 0;
std::from_chars(body.data(), body.data() + body.size(), result);
return result;
}
/// Returns \ref body as double
operator double() const
{
// There's no std::from_chars for floating-point types in a lot of STLs
return std::stod(static_cast<std::string>(body));
}
const header_view& get_header_object(const std::string_view key) const
{
return multipart::get_header_object(headers, key);
}
friend std::ostream& operator<<(std::ostream& stream, const part_view& part)
{
for (const auto& [header_key, header_value] : part.headers)
{
stream << header_key << ": " << header_value.value;
for (const auto& [param_key, param_value] : header_value.params)
{
stream << "; " << param_key << '=' << padded{param_value};
}
stream << crlf;
}
stream << crlf;
stream << part.body << crlf;
return stream;
}
};
/// Multipart map (key is the name parameter).
using mp_view_map = std::unordered_multimap<std::string_view, part_view, ci_hash, ci_key_eq>;
/// The parsed multipart request/response
struct message_view
{
std::reference_wrapper<const ci_map> headers; ///< The request/response headers
std::string boundary; ///< The text boundary that separates different `parts`
std::vector<part_view> parts; ///< The individual parts of the message
mp_view_map part_map; ///< The individual parts of the message, organized in a map with the `name` header parameter being the key
const std::string& get_header_value(const std::string& key) const
{
return crow::get_header_value(headers.get(), key);
}
part_view get_part_by_name(const std::string_view name)
{
mp_view_map::iterator result = part_map.find(name);
if (result != part_map.end())
return result->second;
else
return {};
}
friend std::ostream& operator<<(std::ostream& stream, const message_view message)
{
std::string delimiter = dd + message.boundary;
for (const part_view& part : message.parts)
{
stream << delimiter << crlf;
stream << part;
}
stream << delimiter << dd << crlf;
return stream;
}
/// Represent all parts as a string (**does not include message headers**)
std::string dump() const
{
std::ostringstream str;
str << *this;
return std::move(str).str();
}
/// Represent an individual part as a string
std::string dump(int part_) const
{
std::ostringstream str;
str << parts.at(part_);
return std::move(str).str();
}
/// Default constructor using default values
message_view(const ci_map& headers_, const std::string& boundary_, const std::vector<part_view>& sections):
headers(headers_), boundary(boundary_), parts(sections)
{
for (const part_view& item : parts)
{
part_map.emplace(
(get_header_object(item.headers, "Content-Disposition").params.find("name")->second),
item);
}
}
/// Create a multipart message from a request data
explicit message_view(const request& req):
headers(req.headers),
boundary(get_boundary(get_header_value("Content-Type")))
{
parse_body(req.body);
}
private:
std::string_view get_boundary(const std::string_view header) const
{
constexpr std::string_view boundary_text = "boundary=";
const size_t found = header.find(boundary_text);
if (found == std::string_view::npos)
{
return std::string_view();
}
const std::string_view to_return = header.substr(found + boundary_text.size());
if (to_return[0] == '\"')
{
return to_return.substr(1, to_return.length() - 2);
}
return to_return;
}
void parse_body(std::string_view body)
{
const std::string delimiter = dd + boundary;
// TODO(EDev): Exit on error
while (body != (crlf))
{
const size_t found = body.find(delimiter);
if (found == std::string_view::npos)
{
// did not find delimiter; probably an ill-formed body; ignore the rest
break;
}
const std::string_view 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 = body.substr(found + delimiter.length() + 2);
if (!section.empty())
{
part_view parsed_section = parse_section(section);
part_map.emplace(
(get_header_object(parsed_section.headers, "Content-Disposition").params.find("name")->second),
parsed_section);
parts.push_back(std::move(parsed_section));
}
}
}
part_view parse_section(std::string_view section)
{
constexpr static std::string_view crlf2 = "\r\n\r\n";
const size_t found = section.find(crlf2);
const std::string_view head_line = section.substr(0, found + 2);
section = section.substr(found + 4);
return part_view{
parse_section_head(head_line),
section.substr(0, section.length() - 2),
};
}
mph_view_map parse_section_head(std::string_view lines)
{
mph_view_map result;
while (!lines.empty())
{
header_view to_add;
const size_t found_crlf = lines.find(crlf);
std::string_view line = lines.substr(0, found_crlf);
std::string_view key;
lines = lines.substr(found_crlf + 2);
// Add the header if available
if (!line.empty())
{
const size_t found_semicolon = line.find("; ");
std::string_view header = line.substr(0, found_semicolon);
if (found_semicolon != std::string_view::npos)
line = line.substr(found_semicolon + 2);
else
line = std::string_view();
const size_t header_split = header.find(": ");
key = header.substr(0, header_split);
to_add.value = header.substr(header_split + 2);
}
// Add the parameters
while (!line.empty())
{
const size_t found_semicolon = line.find("; ");
std::string_view param = line.substr(0, found_semicolon);
if (found_semicolon != std::string_view::npos)
line = line.substr(found_semicolon + 2);
else
line = std::string_view();
const size_t param_split = param.find('=');
const std::string_view value = param.substr(param_split + 1);
to_add.params.emplace(param.substr(0, param_split), trim(value));
}
result.emplace(key, to_add);
}
return result;
}
inline std::string_view trim(const std::string_view 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;
}
};
} // namespace multipart
} // namespace crow