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note.c++.web.mongoose.md

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id title desc updated created
11ik08wpa1qg5ikrd0t1vm3
Mongoose
1709952104550
1699858217004

api overview

  • filesystem
  • gen random, byte order convert, Calculate the CRC32 checksum, Get the current millisecond-level timestamp, help operation macro of list
  • url check and extract field (port, host name, user name and user password, uri), buff io, base64(encode, decode, update)
  • MD5 和 SHA-1
  • mg_str and printf api
  • mg_log
  • mg_timer
  • mg_connection
  • mg_dns
  • mg_addrs
  • mg_mgr
    • mg_mgr_poll
    • mg_mgr_init
    • mg_mgr_free
    • mg_listen
    • mg_connect
    • mg_wrapfd
    • mg_send
    • mg_printf
    • 。。。。
  • mg_http
  • mg_mqtt
  • mg_dns
  • mg_json
  • mg_rpc
  • mg_mip(stm32)

http message mapping, and operation

struct to http request

struct mg_str {
  const char *ptr;  // Pointer to string data
  size_t len;       // String len
};
struct mg_http_header {
  struct mg_str name;   // Header name
  struct mg_str value;  // Header value
};
struct mg_http_message {
  struct mg_str method, uri, query, proto;             // Request/response line
  struct mg_http_header headers[MG_MAX_HTTP_HEADERS];  // Headers
  struct mg_str body;                                  // Body
  struct mg_str head;                                  // Request + headers
  struct mg_str chunk;    // Chunk for chunked encoding,  or partial body
  struct mg_str message;  // Request + headers + body
};

struct to http response

// by using mg_http_reply to generate response message return directly
mg_http_reply();

operation

int mg_http_parse(const char *s, size_t len, struct mg_http_message *hm) ;
static void mg_http_parse_headers(const char *s, const char *end,
                                  struct mg_http_header *h, int max_headers);
truct mg_str *mg_http_get_header(struct mg_http_message *h, const char *name);
int mg_url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
                  int is_form_url_encoded);
size_t mg_url_encode(const char *s, size_t n, char *buf, size_t len);
bool mg_http_match_uri(const struct mg_http_message *hm, const char *glob);                  
long mg_http_upload(struct mg_connection *c, struct mg_http_message *hm,
                    struct mg_fs *fs, const char *path, size_t max_size);
void mg_http_reply(struct mg_connection *c, int code, const char *headers,
                   const char *fmt, ...) ;

work api call flow

  1. signal setting
  2. init mg
  3. set address + cb(parse request and reply)
  4. poll
  5. uninit mg

event drive

  1. MG_EV_READ 属于socket事件
  2. MG_EV_HTTP_MSG 属于protocol事件
  3. protocol 事件 与 socket事件 对应不同的handler, 每次mg_call时都分别处理
void mg_call(struct mg_connection *c, int ev, void *ev_data) {
  // Run user-defined handler first, in order to give it an ability
  // to intercept processing (e.g. clean input buffer) before the
  // protocol handler kicks in
  if (c->fn != NULL) 
    c->fn(c, ev, ev_data, c->fn_data);
  if (c->pfn != NULL) 
    c->pfn(c, ev, ev_data, c->pfn_data);
}
  1. socket 事件的handler如何影响protocol事件的处理, 如下代码只会进入read事件直到结束，不会进入httpmsg事件，为何？
static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
  if (ev == MG_EV_READ) {
    // Parse the incoming data ourselves. If we can parse the request,
    // store two size_t variables in the c->data: expected len and recv len.
    size_t *data = (size_t *) c->data;
    printf("===> enter mg read\n");
    if (data[0]) {  // Already parsed, simply print received data
      data[1] += c->recv.len;
      MG_INFO(("Got chunk len %lu, %lu total", c->recv.len, data[1]));
      c->recv.len = 0;  // And cleanup the receive buffer. Streaming!
    //   if (data[1] >= data[0]) mg_http_reply(c, 200, "", "ok\n");
    } else {
        printf("===> enter mg read else\n");
      struct mg_http_message hm;
      int n = mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
      if (n < 0) mg_error(c, "Bad response");
      if (n > 0) {
          static int test_count = 0;
        if (mg_http_match_uri(&hm, "/upload")) {
          MG_INFO(("Got chunk len %lu", c->recv.len - n));
          data[0] = hm.body.len;
          data[1] = c->recv.len - n;
        printf("===> parse success! %d, data0len:%d, data1len:%d\n", test_count++, data[0], data[1]);
        //   if (data[1] >= data[0]) mg_http_reply(c, 200, "", "ok\n");
        } else {
          struct mg_http_serve_opts opts = {.root_dir = "."};
          mg_http_serve_dir(c, &hm, &opts);
        }
      }
    }
  }
 else if (ev == MG_EV_HTTP_MSG) {
    size_t *data = (size_t *) c->data;
    printf("===> enter recive http msg!\n");
    printf("===> recive success! data0len:%d, data1len:%d\n", data[0], data[1]);
  }
  (void) fn_data, (void) ev_data;
}
//static http cb 
static void http_cb(struct mg_connection* c, int ev, void* evd, void* fnd) {
  if (ev == MG_EV_READ || ev == MG_EV_CLOSE) {
    struct mg_http_message hm;
    // mg_hexdump(c->recv.buf, c->recv.len);
    while (c->recv.buf != NULL && c->recv.len > 0) {
      bool next = false;
      int hlen = mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
      .....
      }}}

reason: 手动处理 message 时，清空 connect 长度，以至于进入http_cb时跳出处理

the parse core of http

  1. 按字符串规则进行 固定字段的解析
  2. Content-Length or Transfer-Encoding () for body

由生成消息的一方，统计好 body 长度，将长度信息和 body 一起放入 request 和 response 中 如果该 header 缺失，则采用策略可能为 不断读取 buff 直到 socket close

my oop implementation

  1. inner dependency outside declare and register to focus object
  2. extract obj
  3. to combine each obj and dependency injection. server(vector<connection(vector<router(vector)>)>())
  4. shallow interface abstraction for adapting pure c to c++ oop server -> run()(listen) add_connect() strip_connection() connection -> add_router() set_timeout() router -> add_endpoint() add_common_filter() add_filter() endpoint -> add_handler() parser(friend) -> encode() decode() dto() get() set()

refe

offical: mongoose github: mongoose offical: documentation blog: mongoose blog: 核心处理模块 blog: mongoose7 新特性介绍以及poll过程 blog: mongoose 初始化 blog: Mongoose源码剖析：mongoose的工作模型

已过时，该工作模型描述mongoose v6之前的版本

mongoose websocket 问题

创建客户端链接后，一个线程用于poll等待服务端消息，另一个线程用于异步发送ws消息

  1. 问题1: mg_ws_send 并不会触发poll，对链接进行处理，导致每次发送的消息都是等待到poll超时后才发送到服务端
  2. 按官方例程，发送线程使用 wakeup，在fn中添加wakeup事件的处理，在事件处理时调用mg_ws_send,但存在问题: 现象: 客户端消息没有发送出去就close了，服务端报错请求解析错误
  3. 方案3: 发送线程正常发送，发送后调用 wakeup 只是触发poll