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Merge pull request ipkn#358 from CrowCpp/multipart_improvements
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Improved how multipart messages work
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@The-EDev
The-EDev authored Mar 11, 2022
2 parents 81a1b49 + af81ca9 commit 293ed2c
Showing 1 changed file with 80 additions and 19 deletions.
99 changes: 80 additions & 19 deletions include/crow/multipart.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,44 +6,88 @@

#include "crow/http_request.h"
#include "crow/returnable.h"
#include "crow/ci_map.h"

namespace crow
{

/// Encapsulates anything related to processing and organizing `multipart/xyz` messages
namespace multipart
{

const std::string dd = "--";

/// 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::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`

operator int() const { return std::stoi(value); } ///< Returns \ref value as integer
operator double() const { return std::stod(value); } ///< Returns \ref value as double
};

/// Multipart header map (key is header key).
using mph_map = std::unordered_multimap<std::string, header, ci_hash, ci_key_eq>;

/// Find and return the value object associated with the key. (returns an empty class if nothing is found)
template<typename O, typename T>
inline const O& get_header_value_object(const T& headers, const std::string& key)
{
if (headers.count(key))
{
return headers.find(key)->second;
}
static O empty;
return empty;
}

/// Same as \ref get_header_value_Object() but for \ref multipart.header
template<typename T>
inline const header& get_header_object(const T& headers, const std::string& key)
{
return get_header_value_object<header>(headers, key);
}

///One part of the multipart message

///
/// It is usually separated from other sections by a `boundary`
struct part
{
//TODO(EDev): restructure this to an `unordered_map<string, header>` with string being `header::value.first`
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
mph_map 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

operator int() const { return std::stoi(body); } ///< Returns \ref body as integer
operator double() const { return std::stod(body); } ///< Returns \ref body as double

const header& get_header_object(const std::string& key) const
{
return multipart::get_header_object(headers, key);
}
};

/// Multipart map (key is the name parameter).
using mp_map = std::unordered_multimap<std::string, part, ci_hash, ci_key_eq>;

/// The parsed multipart request/response
struct message : public returnable
{
ci_map headers; ///< The request/response headers
std::string boundary; ///< The text boundary that separates different `parts`
std::vector<part> parts; ///< The individual parts of the message
mp_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, key);
}

part get_part_by_name(const std::string& name)
{
return part_map.find(name)->second;
}

/// Represent all parts as a string (**does not include message headers**)
std::string dump() const override
{
Expand All @@ -64,10 +108,10 @@ namespace crow
{
std::stringstream str;
part item = parts[part_];
for (header item_h : item.headers)
for (auto& item_h : item.headers)
{
str << item_h.value.first << ": " << item_h.value.second;
for (auto& it : item_h.params)
str << item_h.first << ": " << item_h.second.value;
for (auto& it : item_h.second.params)
{
str << "; " << it.first << '=' << pad(it.second);
}
Expand All @@ -80,15 +124,28 @@ namespace crow

/// 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) {}
returnable("multipart/form-data; boundary=CROW-BOUNDARY"), headers(headers), boundary(boundary), parts(sections)
{
if (!boundary.empty())
content_type = "multipart/form-data; boundary=" + boundary;
for (auto& 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
message(const request& req):
returnable("multipart/form-data"),
returnable("multipart/form-data; boundary=CROW-BOUNDARY"),
headers(req.headers),
boundary(get_boundary(get_header_value("Content-Type"))),
parts(parse_body(req.body))
{}
boundary(get_boundary(get_header_value("Content-Type")))
{
if (!boundary.empty())
content_type = "multipart/form-data; boundary=" + boundary;
parse_body(req.body, parts, part_map);
}

private:
std::string get_boundary(const std::string& header) const
Expand All @@ -107,13 +164,12 @@ namespace crow
return std::string();
}

std::vector<part> parse_body(std::string body)
void parse_body(std::string body, std::vector<part>& sections, mp_map& part_map)
{

std::vector<part> sections;

std::string delimiter = dd + boundary;

// TODO(EDev): Exit on error
while (body != (crlf))
{
size_t found = body.find(delimiter);
Expand All @@ -124,10 +180,13 @@ namespace crow
body.erase(0, found + delimiter.length() + 2);
if (!section.empty())
{
sections.emplace_back(parse_section(section));
part parsed_section(parse_section(section));
part_map.emplace(
(get_header_object(parsed_section.headers, "Content-Disposition").params.find("name")->second),
parsed_section);
sections.push_back(std::move(parsed_section));
}
}
return sections;
}

part parse_section(std::string& section)
Expand All @@ -151,6 +210,7 @@ namespace crow

size_t found = lines.find(crlf);
std::string line = lines.substr(0, found);
std::string key;
lines.erase(0, found + 2);
// Add the header if available
if (!line.empty())
Expand All @@ -163,8 +223,9 @@ namespace crow
line = std::string();

size_t header_split = header.find(": ");
key = header.substr(0, header_split);

to_add.value = std::pair<std::string, std::string>(header.substr(0, header_split), header.substr(header_split + 2));
to_add.value = header.substr(header_split + 2);
}

// Add the parameters
Expand All @@ -183,7 +244,7 @@ namespace crow

to_add.params.emplace(param.substr(0, param_split), trim(value));
}
part.headers.emplace_back(to_add);
part.headers.emplace(key, to_add);
}
}

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