Demo: Protocol String Parsing

Demonstrates URL/query extraction, case-insensitive header lookup, and WebSocket Accept calculation.

1. Example Scope

The page mirrors the repository source, CMake target, and current API, with English comments for the relevant calls.

2. Build and Run

cmake --build build --target sttnet_protocol_parsing --parallel
./build/examples/sttnet_protocol_parsing

3. Validation

./build/examples/sttnet_protocol_parsing

Expected: Extracts id=42 rather than userid=7, returns application/json, and computes s3pPLMBiTxaQ9kYGzzhZRbK+xOo=.

4. Complete Source

#include <sttnet.h>

#include <iostream>
#include <string>

int main()
{
    using stt::data::HttpStringUtil;
    using stt::data::WebsocketStringUtil;

    const std::string url="http://127.0.0.1:8080/users?userid=7&id=42&page=2";
    std::string ip;
    int port=0;
    std::string locationAndQuery;
    std::string path;
    std::string query;
    std::string id;

    // These are lightweight extraction helpers. They do not URL-decode percent
    // escapes and are not a standards-complete URI parser for hostile input.
    HttpStringUtil::getIP(url,ip);
    HttpStringUtil::getPort(url,port);
    HttpStringUtil::getLocPara(url,locationAndQuery);
    HttpStringUtil::get_location_str(locationAndQuery,path);
    HttpStringUtil::getPara(locationAndQuery,query);

    // Query keys are matched on field boundaries: "id" does not match "userid".
    HttpStringUtil::get_value_str(locationAndQuery,id,"id");
    std::cout << "ip=" << ip << '\n'
              << "port=" << port << '\n'
              << "location=" << locationAndQuery << '\n'
              << "path=" << path << '\n'
              << "query=" << query << '\n'
              << "id=" << id << '\n';

    const std::string rawHeaders=
        "content-type:\tapplication/json\r\n"
        "Connection: keep-alive\r\n";
    std::string contentType;

    // HTTP field names are case-insensitive. The helper trims optional spaces and
    // tabs after the colon. Server handlers normally use headerValue().
    HttpStringUtil::get_value_header(rawHeaders,contentType,"Content-Type");
    std::cout << "content-type=" << contentType << '\n';

    // This computes RFC 6455 Sec-WebSocket-Accept. Applications normally let the
    // WebSocket server perform the handshake automatically.
    std::string websocketKey="dGhlIHNhbXBsZSBub25jZQ==";
    WebsocketStringUtil::transfer_websocket_key(websocketKey);
    std::cout << "websocket_accept=" << websocketKey << '\n';
    return 0;
}