srs/trunk/src/protocol/srs_http_stack.hpp

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2019 Winlin
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef SRS_PROTOCOL_HTTP_HPP
#define SRS_PROTOCOL_HTTP_HPP

#include <srs_core.hpp>

// Default http listen port.
#define SRS_DEFAULT_HTTP_PORT 80

#if !defined(SRS_EXPORT_LIBRTMP)

#include <map>
#include <string>
#include <vector>

// For srs-librtmp, @see https://github.com/ossrs/srs/issues/213
#ifndef _WIN32
#include <sys/uio.h>
#endif

class SrsFileReader;
class SrsHttpHeader;
class ISrsHttpMessage;
class SrsHttpMuxEntry;
class ISrsHttpResponseWriter;

// From http specification
// CR             = <US-ASCII CR, carriage return (13)>
#define SRS_HTTP_CR SRS_CONSTS_CR // 0x0D
// LF             = <US-ASCII LF, linefeed (10)>
#define SRS_HTTP_LF SRS_CONSTS_LF // 0x0A
// SP             = <US-ASCII SP, space (32)>
#define SRS_HTTP_SP ' ' // 0x20
// HT             = <US-ASCII HT, horizontal-tab (9)>
#define SRS_HTTP_HT '\x09' // 0x09

// HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all
// protocol elements except the entity-body (see appendix 19.3 for
// tolerant applications).
#define SRS_HTTP_CRLF "\r\n" // 0x0D0A
#define SRS_HTTP_CRLFCRLF "\r\n\r\n" // 0x0D0A0D0A

// @see ISrsHttpMessage._http_ts_send_buffer
#define SRS_HTTP_TS_SEND_BUFFER_SIZE 4096

// For ead all of http body, read each time.
#define SRS_HTTP_READ_CACHE_BYTES 4096

// For http parser macros
#define SRS_CONSTS_HTTP_OPTIONS HTTP_OPTIONS
#define SRS_CONSTS_HTTP_GET HTTP_GET
#define SRS_CONSTS_HTTP_POST HTTP_POST
#define SRS_CONSTS_HTTP_PUT HTTP_PUT
#define SRS_CONSTS_HTTP_DELETE HTTP_DELETE

// Error replies to the request with the specified error message and HTTP code.
// The error message should be plain text.
extern srs_error_t srs_go_http_error(ISrsHttpResponseWriter* w, int code);
extern srs_error_t srs_go_http_error(ISrsHttpResponseWriter* w, int code, std::string error);

// Get the status text of code.
extern std::string srs_generate_http_status_text(int status);

// It reports whether a given response status code
// permits a body.  See RFC2616, section 4.4.
extern bool srs_go_http_body_allowd(int status);

// DetectContentType implements the algorithm described
// at http://mimesniff.spec.whatwg.org/ to determine the
// Content-Type of the given data.  It considers at most the
// first 512 bytes of data.  DetectContentType always returns
// a valid MIME type: if it cannot determine a more specific one, it
// returns "application/octet-stream".
extern std::string srs_go_http_detect(char* data, int size);

// The state of HTTP message
enum SrsHttpParseState {
    SrsHttpParseStateInit = 0,
    SrsHttpParseStateStart,
    SrsHttpParseStateHeaderComplete,
    SrsHttpParseStateMessageComplete
};

// A Header represents the key-value pairs in an HTTP header.
class SrsHttpHeader
{
private:
    std::map<std::string, std::string> headers;
public:
    SrsHttpHeader();
    virtual ~SrsHttpHeader();
public:
    // Add adds the key, value pair to the header.
    // It appends to any existing values associated with key.
    virtual void set(std::string key, std::string value);
    // Get gets the first value associated with the given key.
    // If there are no values associated with the key, Get returns "".
    // To access multiple values of a key, access the map directly
    // with CanonicalHeaderKey.
    virtual std::string get(std::string key);
public:
    // Get the content length. -1 if not set.
    virtual int64_t content_length();
    // set the content length by header "Content-Length"
    virtual void set_content_length(int64_t size);
public:
    // Get the content type. empty string if not set.
    virtual std::string content_type();
    // set the content type by header "Content-Type"
    virtual void set_content_type(std::string ct);
public:
    // write all headers to string stream.
    virtual void write(std::stringstream& ss);
};

// A ResponseWriter interface is used by an HTTP handler to
// construct an HTTP response.
// Usage 1, response with specified length content:
//      ISrsHttpResponseWriter* w; // create or get response.
//      std::string msg = "Hello, HTTP!";
//      w->header()->set_content_type("text/plain; charset=utf-8");
//      w->header()->set_content_length(msg.length());
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->write((char*)msg.data(), (int)msg.length());
//      w->final_request(); // optional flush.
// Usage 2, response with HTTP code only, zero content length.
//      ISrsHttpResponseWriter* w; // create or get response.
//      w->header()->set_content_length(0);
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->final_request();
// Usage 3, response in chunked encoding.
//      ISrsHttpResponseWriter* w; // create or get response.
//      std::string msg = "Hello, HTTP!";
//      w->header()->set_content_type("application/octet-stream");
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->final_request(); // required to end the chunked and flush.
class ISrsHttpResponseWriter
{
public:
    ISrsHttpResponseWriter();
    virtual ~ISrsHttpResponseWriter();
public:
    // When chunked mode,
    // final the request to complete the chunked encoding.
    // For no-chunked mode,
    // final to send request, for example, content-length is 0.
    virtual srs_error_t final_request() = 0;
    
    // Header returns the header map that will be sent by WriteHeader.
    // Changing the header after a call to WriteHeader (or Write) has
    // no effect.
    virtual SrsHttpHeader* header() = 0;
    
    // Write writes the data to the connection as part of an HTTP reply.
    // If WriteHeader has not yet been called, Write calls WriteHeader(http.StatusOK)
    // before writing the data.  If the Header does not contain a
    // Content-Type line, Write adds a Content-Type set to the result of passing
    // The initial 512 bytes of written data to DetectContentType.
    // @param data, the data to send. NULL to flush header only.
    virtual srs_error_t write(char* data, int size) = 0;
    // for the HTTP FLV, to writev to improve performance.
    // @see https://github.com/ossrs/srs/issues/405
    virtual srs_error_t writev(const iovec* iov, int iovcnt, ssize_t* pnwrite) = 0;
    
    // WriteHeader sends an HTTP response header with status code.
    // If WriteHeader is not called explicitly, the first call to Write
    // will trigger an implicit WriteHeader(http.StatusOK).
    // Thus explicit calls to WriteHeader are mainly used to
    // send error codes.
    // @remark, user must set header then write or write_header.
    virtual void write_header(int code) = 0;
};

// The reader interface for http response.
class ISrsHttpResponseReader
{
public:
    ISrsHttpResponseReader();
    virtual ~ISrsHttpResponseReader();
public:
    // Whether response read EOF.
    virtual bool eof() = 0;
    // Read from the response body.
    // @param data, the buffer to read data buffer to.
    // @param nb_data, the max size of data buffer.
    // @param nb_read, the actual read size of bytes. NULL to ignore.
    // @remark when eof(), return error.
    // @remark for some server, the content-length not specified and not chunked,
    //      which is actually the infinite chunked encoding, which after http header
    //      is http response data, it's ok for browser. that is,
    //      when user call this read, please ensure there is data to read(by content-length
    //      or by chunked), because the sdk never know whether there is no data or
    //      infinite chunked.
    virtual srs_error_t read(char* data, int nb_data, int* nb_read) = 0;
};

// Objects implementing the Handler interface can be
// registered to serve a particular path or subtree
// in the HTTP server.
//
// ServeHTTP should write reply headers and data to the ResponseWriter
// and then return.  Returning signals that the request is finished
// and that the HTTP server can move on to the next request on
// The connection.
class ISrsHttpHandler
{
public:
    SrsHttpMuxEntry* entry;
public:
    ISrsHttpHandler();
    virtual ~ISrsHttpHandler();
public:
    virtual bool is_not_found();
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r) = 0;
};

// Redirect to a fixed URL
class SrsHttpRedirectHandler : public ISrsHttpHandler
{
private:
    std::string url;
    int code;
public:
    SrsHttpRedirectHandler(std::string u, int c);
    virtual ~SrsHttpRedirectHandler();
public:
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
};

// NotFound replies to the request with an HTTP 404 not found error.
class SrsHttpNotFoundHandler : public ISrsHttpHandler
{
public:
    SrsHttpNotFoundHandler();
    virtual ~SrsHttpNotFoundHandler();
public:
    virtual bool is_not_found();
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
};

// FileServer returns a handler that serves HTTP requests
// with the contents of the file system rooted at root.
//
// To use the operating system's file system implementation,
// use http.Dir:
//
//     http.Handle("/", SrsHttpFileServer("/tmp"))
//     http.Handle("/", SrsHttpFileServer("static-dir"))
class SrsHttpFileServer : public ISrsHttpHandler
{
protected:
    std::string dir;
public:
    SrsHttpFileServer(std::string root_dir);
    virtual ~SrsHttpFileServer();
public:
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
private:
    // Serve the file by specified path
    virtual srs_error_t serve_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
    virtual srs_error_t serve_flv_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
    virtual srs_error_t serve_mp4_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
protected:
    // When access flv file with x.flv?start=xxx
    virtual srs_error_t serve_flv_stream(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath, int offset);
    // When access mp4 file with x.mp4?range=start-end
    // @param start the start offset in bytes.
    // @param end the end offset in bytes. -1 to end of file.
    // @remark response data in [start, end].
    virtual srs_error_t serve_mp4_stream(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath, int start, int end);
protected:
    // Copy the fs to response writer in size bytes.
    virtual srs_error_t copy(ISrsHttpResponseWriter* w, SrsFileReader* fs, ISrsHttpMessage* r, int size);
};

// The mux entry for server mux.
// The matcher info, for example, the pattern and handler.
class SrsHttpMuxEntry
{
public:
    bool explicit_match;
    ISrsHttpHandler* handler;
    std::string pattern;
    bool enabled;
public:
    SrsHttpMuxEntry();
    virtual ~SrsHttpMuxEntry();
};

// The hijacker for http pattern match.
class ISrsHttpMatchHijacker
{
public:
    ISrsHttpMatchHijacker();
    virtual ~ISrsHttpMatchHijacker();
public:
    // When match the request failed, no handler to process request.
    // @param request the http request message to match the handler.
    // @param ph the already matched handler, hijack can rewrite it.
    virtual srs_error_t hijack(ISrsHttpMessage* request, ISrsHttpHandler** ph) = 0;
};

// The server mux, all http server should implements it.
class ISrsHttpServeMux
{
public:
    ISrsHttpServeMux();
    virtual ~ISrsHttpServeMux();
public:
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r) = 0;
};

// ServeMux is an HTTP request multiplexer.
// It matches the URL of each incoming request against a list of registered
// patterns and calls the handler for the pattern that
// most closely matches the URL.
//
// Patterns name fixed, rooted paths, like "/favicon.ico",
// or rooted subtrees, like "/images/" (note the trailing slash).
// Longer patterns take precedence over shorter ones, so that
// if there are handlers registered for both "/images/"
// and "/images/thumbnails/", the latter handler will be
// called for paths beginning "/images/thumbnails/" and the
// former will receive requests for any other paths in the
// "/images/" subtree.
//
// Note that since a pattern ending in a slash names a rooted subtree,
// The pattern "/" matches all paths not matched by other registered
// patterns, not just the URL with Path == "/".
//
// Patterns may optionally begin with a host name, restricting matches to
// URLs on that host only.  Host-specific patterns take precedence over
// general patterns, so that a handler might register for the two patterns
// "/codesearch" and "codesearch.google.com/" without also taking over
// requests for "http://www.google.com/".
//
// ServeMux also takes care of sanitizing the URL request path,
// redirecting any request containing . or .. elements to an
// equivalent .- and ..-free URL.
class SrsHttpServeMux : public ISrsHttpServeMux
{
private:
    // The pattern handler, to handle the http request.
    std::map<std::string, SrsHttpMuxEntry*> entries;
    // The vhost handler.
    // When find the handler to process the request,
    // append the matched vhost when pattern not starts with /,
    // For example, for pattern /live/livestream.flv of vhost ossrs.net,
    // The path will rewrite to ossrs.net/live/livestream.flv
    std::map<std::string, ISrsHttpHandler*> vhosts;
    // all hijackers for http match.
    // For example, the hstrs(http stream trigger rtmp source)
    // can hijack and install handler when request incoming and no handler.
    std::vector<ISrsHttpMatchHijacker*> hijackers;
public:
    SrsHttpServeMux();
    virtual ~SrsHttpServeMux();
public:
    // Initialize the http serve mux.
    virtual srs_error_t initialize();
    // hijack the http match.
    virtual void hijack(ISrsHttpMatchHijacker* h);
    virtual void unhijack(ISrsHttpMatchHijacker* h);
public:
    // Handle registers the handler for the given pattern.
    // If a handler already exists for pattern, Handle panics.
    virtual srs_error_t handle(std::string pattern, ISrsHttpHandler* handler);
// interface ISrsHttpServeMux
public:
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
public:
    virtual srs_error_t find_handler(ISrsHttpMessage* r, ISrsHttpHandler** ph);
private:
    virtual srs_error_t match(ISrsHttpMessage* r, ISrsHttpHandler** ph);
    virtual bool path_match(std::string pattern, std::string path);
};

// The filter http mux, directly serve the http CORS requests,
// while proxy to the worker mux for services.
class SrsHttpCorsMux : public ISrsHttpServeMux
{
private:
    bool required;
    bool enabled;
    ISrsHttpServeMux* next;
public:
    SrsHttpCorsMux();
    virtual ~SrsHttpCorsMux();
public:
    virtual srs_error_t initialize(ISrsHttpServeMux* worker, bool cros_enabled);
// interface ISrsHttpServeMux
public:
    virtual srs_error_t serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
};

// For http header.
typedef std::pair<std::string, std::string> SrsHttpHeaderField;

// A Request represents an HTTP request received by a server
// or to be sent by a client.
//
// The field semantics differ slightly between client and server
// usage. In addition to the notes on the fields below, see the
// documentation for Request.Write and RoundTripper.
//
// There are some modes to determine the length of body:
//      1. content-length and chunked.
//      2. user confirmed infinite chunked.
//      3. no body or user not confirmed infinite chunked.
// For example:
//      ISrsHttpMessage* r = ...;
//      while (!r->eof()) r->read(); // Read in mode 1 or 3.
// For some server, we can confirm the body is infinite chunked:
//      ISrsHttpMessage* r = ...;
//      r->enter_infinite_chunked();
//      while (!r->eof()) r->read(); // Read in mode 2
// @rmark for mode 2, the infinite chunked, all left data is body.
class ISrsHttpMessage
{
private:
    // Use a buffer to read and send ts file.
    // TODO: FIXME: remove it.
    char* _http_ts_send_buffer;
public:
    ISrsHttpMessage();
    virtual ~ISrsHttpMessage();
public:
    // The http request level cache.
    virtual char* http_ts_send_buffer();
public:
    virtual uint8_t method() = 0;
    virtual uint16_t status_code() = 0;
    // Method helpers.
    virtual std::string method_str() = 0;
    virtual bool is_http_get() = 0;
    virtual bool is_http_put() = 0;
    virtual bool is_http_post() = 0;
    virtual bool is_http_delete() = 0;
    virtual bool is_http_options() = 0;
public:
    // Whether should keep the connection alive.
    virtual bool is_keep_alive() = 0;
    // The uri contains the host and path.
    virtual std::string uri() = 0;
    // The url maybe the path.
    virtual std::string url() = 0;
    virtual std::string host() = 0;
    virtual std::string path() = 0;
    virtual std::string query() = 0;
    virtual std::string ext() = 0;
    // Get the RESTful id,
    // for example, pattern is /api/v1/streams, path is /api/v1/streams/100,
    // then the rest id is 100.
    // @param pattern the handler pattern which will serve the request.
    // @return the REST id; -1 if not matched.
    virtual int parse_rest_id(std::string pattern) = 0;
public:
    // The left all data is chunked body, the infinite chunked mode,
    // which is chunked encoding without chunked header.
    // @remark error when message is in chunked or content-length specified.
    virtual srs_error_t enter_infinite_chunked() = 0;
    // Read body to string.
    // @remark for small http body.
    virtual srs_error_t body_read_all(std::string& body) = 0;
    // Get the body reader, to read one by one.
    // @remark when body is very large, or chunked, use this.
    virtual ISrsHttpResponseReader* body_reader() = 0;
    // The content length, -1 for chunked or not set.
    virtual int64_t content_length() = 0;
public:
    // Get the param in query string,
    // for instance, query is "start=100&end=200",
    // then query_get("start") is "100", and query_get("end") is "200"
    virtual std::string query_get(std::string key) = 0;
    // Get the headers.
    virtual int request_header_count() = 0;
    virtual std::string request_header_key_at(int index) = 0;
    virtual std::string request_header_value_at(int index) = 0;
public:
    // Whether the current request is JSONP,
    // which has a "callback=xxx" in QueryString.
    virtual bool is_jsonp() = 0;
};

// Used to resolve the http uri.
class SrsHttpUri
{
private:
    std::string url;
    std::string schema;
    std::string host;
    int port;
    std::string path;
    std::string query;
public:
    SrsHttpUri();
    virtual ~SrsHttpUri();
public:
    // Initialize the http uri.
    virtual srs_error_t initialize(std::string _url);
public:
    virtual std::string get_url();
    virtual std::string get_schema();
    virtual std::string get_host();
    virtual int get_port();
    virtual std::string get_path();
    virtual std::string get_query();
private:
    // Get the parsed url field.
    // @return return empty string if not set.
    virtual std::string get_uri_field(std::string uri, void* hp_u, int field);
};

#endif

// The http-parser is license under MIT at https://github.com/nodejs/http-parser/blob/master/LICENSE-MIT
// Version: 2.1 from https://github.com/nodejs/http-parser/releases/tag/v2.1
// File: https://github.com/nodejs/http-parser/blob/80819384450b5511a3d1c424dd92a5843c891364/http_parser.h

//Copyright Joyent, Inc. and other Node contributors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// The SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
#ifndef http_parser_h
#define http_parser_h
#ifdef __cplusplus
extern "C" {
#endif
    
#define HTTP_PARSER_VERSION_MAJOR 2
#define HTTP_PARSER_VERSION_MINOR 1
    
#include <sys/types.h>
#if defined(_WIN32) && !defined(__MINGW32__) && (!defined(_MSC_VER) || _MSC_VER<1600)
#include <BaseTsd.h>
#include <stddef.h>
    typedef __int8 int8_t;
    typedef unsigned __int8 uint8_t;
    typedef __int16 int16_t;
    typedef unsigned __int16 uint16_t;
    typedef __int32 int32_t;
    typedef unsigned __int32 uint32_t;
    typedef __int64 int64_t;
    typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif
    
    // Compile with -DHTTP_PARSER_STRICT=0 to make less checks, but run
    // faster
#ifndef HTTP_PARSER_STRICT
# define HTTP_PARSER_STRICT 1
#endif
    
    /* Maximium header size allowed */
#define HTTP_MAX_HEADER_SIZE (80*1024)
    
    
    typedef struct http_parser http_parser;
    typedef struct http_parser_settings http_parser_settings;
    
    
    // Callbacks should return non-zero to indicate an error. The parser will
    // then halt execution.
    //
    // The one exception is on_headers_complete. In a HTTP_RESPONSE parser
    // returning '1' from on_headers_complete will tell the parser that it
    // should not expect a body. This is used when receiving a response to a
    // HEAD request which may contain 'Content-Length' or 'Transfer-Encoding:
    // chunked' headers that indicate the presence of a body.
    //
    // http_data_cb does not return data chunks. It will be call arbitrarally
    // many times for each string. E.G. you might get 10 callbacks for "on_url"
    // each providing just a few characters more data.
    typedef int (*http_data_cb) (http_parser*, const char *at, size_t length);
    typedef int (*http_cb) (http_parser*);
    
    
    /* Request Methods */
#define HTTP_METHOD_MAP(XX)         \
    XX(0,  DELETE,      DELETE)       \
    XX(1,  GET,         GET)          \
    XX(2,  HEAD,        HEAD)         \
    XX(3,  POST,        POST)         \
    XX(4,  PUT,         PUT)          \
    /* pathological */                \
    XX(5,  CONNECT,     CONNECT)      \
    XX(6,  OPTIONS,     OPTIONS)      \
    XX(7,  TRACE,       TRACE)        \
    /* webdav */                      \
    XX(8,  COPY,        COPY)         \
    XX(9,  LOCK,        LOCK)         \
    XX(10, MKCOL,       MKCOL)        \
    XX(11, MOVE,        MOVE)         \
    XX(12, PROPFIND,    PROPFIND)     \
    XX(13, PROPPATCH,   PROPPATCH)    \
    XX(14, SEARCH,      SEARCH)       \
    XX(15, UNLOCK,      UNLOCK)       \
    /* subversion */                  \
    XX(16, REPORT,      REPORT)       \
    XX(17, MKACTIVITY,  MKACTIVITY)   \
    XX(18, CHECKOUT,    CHECKOUT)     \
    XX(19, MERGE,       MERGE)        \
    /* upnp */                        \
    XX(20, MSEARCH,     M-SEARCH)     \
    XX(21, NOTIFY,      NOTIFY)       \
    XX(22, SUBSCRIBE,   SUBSCRIBE)    \
    XX(23, UNSUBSCRIBE, UNSUBSCRIBE)  \
    /* RFC-5789 */                    \
    XX(24, PATCH,       PATCH)        \
    XX(25, PURGE,       PURGE)        \

    enum http_method
    {
#define XX(num, name, string) HTTP_##name = num,
        HTTP_METHOD_MAP(XX)
#undef XX
    };
    
    
    enum http_parser_type { HTTP_REQUEST, HTTP_RESPONSE, HTTP_BOTH };
    
    
    /* Flag values for http_parser.flags field */
    enum flags
    { F_CHUNKED               = 1 << 0
        , F_CONNECTION_KEEP_ALIVE = 1 << 1
        , F_CONNECTION_CLOSE      = 1 << 2
        , F_TRAILING              = 1 << 3
        , F_UPGRADE               = 1 << 4
        , F_SKIPBODY              = 1 << 5
    };
    
    
    // Map for errno-related constants
    // The provided argument should be a macro that takes 2 arguments.
#define HTTP_ERRNO_MAP(XX)                                           \
    /* No error */                                                     \
    XX(OK, "success")                                                  \
    \
    /* Callback-related errors */                                      \
    XX(CB_message_begin, "the on_message_begin callback failed")       \
    XX(CB_status_complete, "the on_status_complete callback failed")   \
    XX(CB_url, "the on_url callback failed")                           \
    XX(CB_header_field, "the on_header_field callback failed")         \
    XX(CB_header_value, "the on_header_value callback failed")         \
    XX(CB_headers_complete, "the on_headers_complete callback failed") \
    XX(CB_body, "the on_body callback failed")                         \
    XX(CB_message_complete, "the on_message_complete callback failed") \
    \
    /* Parsing-related errors */                                       \
    XX(INVALID_EOF_STATE, "stream ended at an unexpected time")        \
    XX(HEADER_OVERFLOW,                                                \
    "too many header bytes seen; overflow detected")                \
    XX(CLOSED_CONNECTION,                                              \
    "data received after completed connection: close message")      \
    XX(INVALID_VERSION, "invalid HTTP version")                        \
    XX(INVALID_STATUS, "invalid HTTP status code")                     \
    XX(INVALID_METHOD, "invalid HTTP method")                          \
    XX(INVALID_URL, "invalid URL")                                     \
    XX(INVALID_HOST, "invalid host")                                   \
    XX(INVALID_PORT, "invalid port")                                   \
    XX(INVALID_PATH, "invalid path")                                   \
    XX(INVALID_QUERY_STRING, "invalid query string")                   \
    XX(INVALID_FRAGMENT, "invalid fragment")                           \
    XX(LF_EXPECTED, "LF character expected")                           \
    XX(INVALID_HEADER_TOKEN, "invalid character in header")            \
    XX(INVALID_CONTENT_LENGTH,                                         \
    "invalid character in content-length header")                   \
    XX(INVALID_CHUNK_SIZE,                                             \
    "invalid character in chunk size header")                       \
    XX(INVALID_CONSTANT, "invalid constant string")                    \
    XX(INVALID_INTERNAL_STATE, "encountered unexpected internal state")\
    XX(STRICT, "strict mode assertion failed")                         \
    XX(PAUSED, "parser is paused")                                     \
    XX(UNKNOWN, "an unknown error occurred")
    
    
    /* Define HPE_* values for each errno value above */
#define HTTP_ERRNO_GEN(n, s) HPE_##n,
    enum http_errno {
        HTTP_ERRNO_MAP(HTTP_ERRNO_GEN)
    };
#undef HTTP_ERRNO_GEN
    
    
    /* Get an http_errno value from an http_parser */
#define HTTP_PARSER_ERRNO(p)            ((enum http_errno) (p)->http_errno)
    
    
    struct http_parser {
        /** PRIVATE **/
        unsigned char type : 2;     /* enum http_parser_type */
        unsigned char flags : 6;    /* F_* values from 'flags' enum; semi-public */
        unsigned char state;        /* enum state from http_parser.c */
        unsigned char header_state; /* enum header_state from http_parser.c */
        unsigned char index;        /* index into current matcher */
        
        uint32_t nread;          /* # bytes read in various scenarios */
        uint64_t content_length; /* # bytes in body (0 if no Content-Length header) */
        
        /** READ-ONLY **/
        unsigned short http_major;
        unsigned short http_minor;
        unsigned short status_code; /* responses only */
        unsigned char method;       /* requests only */
        unsigned char http_errno : 7;
        
        // 1 = Upgrade header was present and the parser has exited because of that.
        // 0 = No upgrade header present.
        // Should be checked when http_parser_execute() returns in addition to
        // error checking.
        unsigned char upgrade : 1;
        
        /** PUBLIC **/
        void *data; /* A pointer to get hook to the "connection" or "socket" object */
    };
    
    
    struct http_parser_settings {
        http_cb      on_message_begin;
        http_data_cb on_url;
        http_cb      on_status_complete;
        http_data_cb on_header_field;
        http_data_cb on_header_value;
        http_cb      on_headers_complete;
        http_data_cb on_body;
        http_cb      on_message_complete;
    };
    
    
    enum http_parser_url_fields
    { UF_SCHEMA           = 0
        , UF_HOST             = 1
        , UF_PORT             = 2
        , UF_PATH             = 3
        , UF_QUERY            = 4
        , UF_FRAGMENT         = 5
        , UF_USERINFO         = 6
        , UF_MAX              = 7
    };
    
    
    // Result structure for http_parser_parse_url().
    // Callers should index into field_data[] with UF_* values iff field_set
    // has the relevant (1 << UF_*) bit set. As a courtesy to clients (and
    // because we probably have padding left over), we convert any port to
    // a uint16_t.
    struct http_parser_url {
        uint16_t field_set;           /* Bitmask of (1 << UF_*) values */
        uint16_t port;                /* Converted UF_PORT string */
        
        struct {
            uint16_t off;               /* Offset into buffer in which field starts */
            uint16_t len;               /* Length of run in buffer */
        } field_data[UF_MAX];
    };
    
    
    void http_parser_init(http_parser *parser, enum http_parser_type type);
    
    
    size_t http_parser_execute(http_parser *parser,
                               const http_parser_settings *settings,
                               const char *data,
                               size_t len);
    
    
    // If http_should_keep_alive() in the on_headers_complete or
    // on_message_complete callback returns 0, then this should be
    // The last message on the connection.
    // If you are the server, respond with the "Connection: close" header.
    // If you are the client, close the connection.
    int http_should_keep_alive(const http_parser *parser);
    
    /* Returns a string version of the HTTP method. */
    const char *http_method_str(enum http_method m);
    
    /* Return a string name of the given error */
    const char *http_errno_name(enum http_errno err);
    
    /* Return a string description of the given error */
    const char *http_errno_description(enum http_errno err);
    
    /* Parse a URL; return nonzero on failure */
    int http_parser_parse_url(const char *buf, size_t buflen,
                              int is_connect,
                              struct http_parser_url *u);
    
    /* Pause or un-pause the parser; a nonzero value pauses */
    void http_parser_pause(http_parser *parser, int paused);
    
    /* Checks if this is the final chunk of the body. */
    int http_body_is_final(const http_parser *parser);
    
#ifdef __cplusplus
}
#endif
#endif

#endif