# Crow: include/crow/http_response.h Source File

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http_response.h
#pragma once
#include <string>
#include <unordered_map>
#include <ios>
#include <fstream>
#include <sstream>
// S_ISREG is not defined for windows
// This defines it like suggested in https://stackoverflow.com/a/62371749
#if defined(_MSC_VER)
#define _CRT_INTERNAL_NONSTDC_NAMES 1
#endif
#include <sys/stat.h>
#if !defined(S_ISREG) && defined(S_IFMT) && defined(S_IFREG)
#define S_ISREG(m) (((m)&S_IFMT) == S_IFREG)
#endif
#include "crow/http_request.h"
#include "crow/ci_map.h"
#include "crow/socket_adaptors.h"
#include "crow/logging.h"
#include "crow/mime_types.h"
#include "crow/returnable.h"
namespace crow
{
template<typename Adaptor, typename Handler, typename... Middlewares>
class Connection;
class Router;
/// HTTP response
struct response
{
template<typename Adaptor, typename Handler, typename... Middlewares>
friend class crow::Connection;
friend class Router;
int code{200}; ///< The Status code for the response.
std::string body; ///< The actual payload containing the response data.
ci_map headers; ///< HTTP headers.
#ifdef CROW_ENABLE_COMPRESSION
bool compressed = true; ///< If compression is enabled and this is false, the individual response will not be compressed.
#endif
bool skip_body = false; ///< Whether this is a response to a HEAD request.
bool manual_length_header = false; ///< Whether Crow should automatically add a "Content-Length" header.
/// Set the value of an existing header in the response.
void set_header(std::string key, std::string value)
{
headers.erase(key);
headers.emplace(std::move(key), std::move(value));
}
/// Add a new header to the response.
void add_header(std::string key, std::string value)
{
headers.emplace(std::move(key), std::move(value));
}
const std::string& get_header_value(const std::string& key)
{
return crow::get_header_value(headers, key);
}
// naive validation of a mime-type string
static bool validate_mime_type(const std::string& candidate) noexcept
{
// Here we simply check that the candidate type starts with
// a valid parent type, and has at least one character afterwards.
std::array<std::string, 10> valid_parent_types = {
"application/", "audio/", "font/", "example/",
"image/", "message/", "model/", "multipart/",
"text/", "video/"};
for (const std::string& parent : valid_parent_types)
{
// ensure the candidate is *longer* than the parent,
// to avoid unnecessary string comparison and to
// reject zero-length subtypes.
if (candidate.size() <= parent.size())
{
continue;
}
// strncmp is used rather than substr to avoid allocation,
// but a string_view approach would be better if Crow
// migrates to C++17.
if (strncmp(parent.c_str(), candidate.c_str(), parent.size()) == 0)
{
return true;
}
}
return false;
}
// Find the mime type from the content type either by lookup,
// or by the content type itself, if it is a valid a mime type.
// Defaults to text/plain.
static std::string get_mime_type(const std::string& contentType)
{
const auto mimeTypeIterator = mime_types.find(contentType);
if (mimeTypeIterator != mime_types.end())
{
return mimeTypeIterator->second;
}
else if (validate_mime_type(contentType))
{
return contentType;
}
else
{
CROW_LOG_WARNING << "Unable to interpret mime type for content type '" << contentType << "'. Defaulting to text/plain.";
return "text/plain";
}
}
// clang-format off
response() {}
explicit response(int code) : code(code) {}
response(std::string body) : body(std::move(body)) {}
response(int code, std::string body) : code(code), body(std::move(body)) {}
// clang-format on
response(returnable&& value)
{
body = value.dump();
set_header("Content-Type", value.content_type);
}
response(returnable& value)
{
body = value.dump();
set_header("Content-Type", value.content_type);
}
response(int code, returnable& value):
code(code)
{
body = value.dump();
set_header("Content-Type", value.content_type);
}
response(int code, returnable&& value):
code(code), body(value.dump())
{
set_header("Content-Type", std::move(value.content_type));
}
response(response&& r)
{
*this = std::move(r);
}
response(std::string contentType, std::string body):
body(std::move(body))
{
set_header("Content-Type", get_mime_type(contentType));
}
response(int code, std::string contentType, std::string body):
code(code), body(std::move(body))
{
set_header("Content-Type", get_mime_type(contentType));
}
response& operator=(const response& r) = delete;
response& operator=(response&& r) noexcept
{
body = std::move(r.body);
code = r.code;
headers = std::move(r.headers);
completed_ = r.completed_;
file_info = std::move(r.file_info);
return *this;
}
/// Check if the response has completed (whether response.end() has been called)
bool is_completed() const noexcept
{
return completed_;
}
void clear()
{
body.clear();
code = 200;
headers.clear();
completed_ = false;
file_info = static_file_info{};
}
/// Return a "Temporary Redirect" response.
///
/// Location can either be a route or a full URL.
void redirect(const std::string& location)
{
code = 307;
set_header("Location", location);
}
/// Return a "Permanent Redirect" response.
///
/// Location can either be a route or a full URL.
void redirect_perm(const std::string& location)
{
code = 308;
set_header("Location", location);
}
/// Return a "Found (Moved Temporarily)" response.
///
/// Location can either be a route or a full URL.
void moved(const std::string& location)
{
code = 302;
set_header("Location", location);
}
/// Return a "Moved Permanently" response.
///
/// Location can either be a route or a full URL.
void moved_perm(const std::string& location)
{
code = 301;
set_header("Location", location);
}
void write(const std::string& body_part)
{
body += body_part;
}
/// Set the response completion flag and call the handler (to send the response).
void end()
{
if (!completed_)
{
completed_ = true;
if (skip_body)
{
set_header("Content-Length", std::to_string(body.size()));
body = "";
manual_length_header = true;
}
if (complete_request_handler_)
{
complete_request_handler_();
manual_length_header = false;
skip_body = false;
}
}
}
/// Same as end() except it adds a body part right before ending.
void end(const std::string& body_part)
{
body += body_part;
end();
}
/// Check if the connection is still alive (usually by checking the socket status).
bool is_alive()
{
return is_alive_helper_ && is_alive_helper_();
}
/// Check whether the response has a static file defined.
bool is_static_type()
{
return file_info.path.size();
}
/// This constains metadata (coming from the `stat` command) related to any static files associated with this response.
///
/// Either a static file or a string body can be returned as 1 response.
struct static_file_info
{
std::string path = "";
struct stat statbuf;
int statResult;
};
/// Return a static file as the response body
void set_static_file_info(std::string path)
{
utility::sanitize_filename(path);
set_static_file_info_unsafe(path);
}
/// Return a static file as the response body without sanitizing the path (use set_static_file_info instead)
void set_static_file_info_unsafe(std::string path)
{
file_info.path = path;
file_info.statResult = stat(file_info.path.c_str(), &file_info.statbuf);
#ifdef CROW_ENABLE_COMPRESSION
compressed = false;
#endif
if (file_info.statResult == 0 && S_ISREG(file_info.statbuf.st_mode))
{
std::size_t last_dot = path.find_last_of(".");
std::string extension = path.substr(last_dot + 1);
code = 200;
this->add_header("Content-Length", std::to_string(file_info.statbuf.st_size));
if (!extension.empty())
{
this->add_header("Content-Type", get_mime_type(extension));
}
}
else
{
code = 404;
file_info.path.clear();
}
}
private:
bool completed_{};
std::function<void()> complete_request_handler_;
std::function<bool()> is_alive_helper_;
static_file_info file_info;
};
} // namespace crow
crow::Connection
An HTTP connection.
Definition http_connection.h:48
crow::Router
Handles matching requests to existing rules and upgrade requests.
Definition routing.h:1254
crow
The main namespace of the library. In this namespace is defined the most important classes and functi...
crow::get_header_value
const std::string & get_header_value(const T &headers, const std::string &key)
Find and return the value associated with the key. (returns an empty string if nothing is found)
Definition http_request.h:24
crow::response::static_file_info
This constains metadata (coming from the stat command) related to any static files associated with th...
Definition http_response.h:281
crow::response
HTTP response.
Definition http_response.h:34
crow::response::end
void end(const std::string &body_part)
Same as end() except it adds a body part right before ending.
Definition http_response.h:258
crow::response::add_header
void add_header(std::string key, std::string value)
Add a new header to the response.
Definition http_response.h:58
crow::response::skip_body
bool skip_body
Whether this is a response to a HEAD request.
Definition http_response.h:47
crow::response::moved
void moved(const std::string &location)
Return a "Found (Moved Temporarily)" response.
Definition http_response.h:215
crow::response::set_static_file_info
void set_static_file_info(std::string path)
Return a static file as the response body.
Definition http_response.h:288
crow::response::manual_length_header
bool manual_length_header
Whether Crow should automatically add a "Content-Length" header.
Definition http_response.h:48
crow::response::redirect_perm
void redirect_perm(const std::string &location)
Return a "Permanent Redirect" response.
Definition http_response.h:205
crow::response::moved_perm
void moved_perm(const std::string &location)
Return a "Moved Permanently" response.
Definition http_response.h:225
crow::response::is_completed
bool is_completed() const noexcept
Check if the response has completed (whether response.end() has been called)
Definition http_response.h:177
crow::response::code
int code
The Status code for the response.
Definition http_response.h:40
crow::response::set_header
void set_header(std::string key, std::string value)
Set the value of an existing header in the response.
Definition http_response.h:51
crow::response::end
void end()
Set the response completion flag and call the handler (to send the response).
Definition http_response.h:237
crow::response::redirect
void redirect(const std::string &location)
Return a "Temporary Redirect" response.
Definition http_response.h:195
crow::response::is_alive
bool is_alive()
Check if the connection is still alive (usually by checking the socket status).
Definition http_response.h:265
crow::response::set_static_file_info_unsafe
void set_static_file_info_unsafe(std::string path)
Return a static file as the response body without sanitizing the path (use set_static_file_info inste...
Definition http_response.h:295
crow::response::headers
ci_map headers
HTTP headers.
Definition http_response.h:42
crow::response::body
std::string body
The actual payload containing the response data.
Definition http_response.h:41
crow::response::compressed
bool compressed
If compression is enabled and this is false, the individual response will not be compressed.
Definition http_response.h:45
crow::response::is_static_type
bool is_static_type()
Check whether the response has a static file defined.
Definition http_response.h:271