add: exercise answer for chapter 6 and 7

2025-12-17 12:44:40 +03:00 · 2018-05-06 14:58:02 +02:00
parent d75f10db41
commit 70250c2b0a
11 changed files with 668 additions and 0 deletions
--- a/exercises/6/handler.hpp
+++ b/exercises/6/handler.hpp
@@ -0,0 +1,96 @@
+//
+// handler.hpp
+// web_server
+// created by changkun at changkun.de/modern-cpp
+//
+
+#include "server.base.hpp"
+#include <fstream>
+
+using namespace std;
+using namespace LabexWeb;
+
+template<typename SERVER_TYPE>
+void start_server(SERVER_TYPE &server) {
+    // resources request
+
+    // processing POST /string, return the string from POST
+    server.resource["^/string/?$"]["POST"] = [](ostream& response, Request& request) {
+        // fetch string from istream (*request.content)
+        stringstream ss;
+        *request.content >> ss.rdbuf();     // read request to stringstream
+        string content=ss.str();
+
+        // return response
+        response << "HTTP/1.1 200 OK\r\nContent-Length: " << content.length() << "\r\n\r\n" << content;
+    };
+
+    // process GET request from /info, return response
+    server.resource["^/info/?$"]["GET"] = [](ostream& response, Request& request) {
+        stringstream content_stream;
+        content_stream << "<h1>Request:</h1>";
+        content_stream << request.method << " " << request.path << " HTTP/" << request.http_version << "<br>";
+        for(auto& header: request.header) {
+            content_stream << header.first << ": " << header.second << "<br>";
+        }
+
+        // get the length of content_stream (use content.tellp() to get)
+        content_stream.seekp(0, ios::end);
+
+        response <<  "HTTP/1.1 200 OK\r\nContent-Length: " << content_stream.tellp() << "\r\n\r\n" << content_stream.rdbuf();
+    };
+
+    // process GET request for /match/[digit+numbers], e.g. GET request is /match/abc123, will return abc123
+    server.resource["^/match/([0-9a-zA-Z]+)/?$"]["GET"] = [](ostream& response, Request& request) {
+        string number=request.path_match[1];
+        response << "HTTP/1.1 200 OK\r\nContent-Length: " << number.length() << "\r\n\r\n" << number;
+    };
+
+    // peocess default GET request; anonymous function will be called if no other matches
+    // response files in folder web/
+    // default: index.html
+    server.default_resource["^/?(.*)$"]["GET"] = [](ostream& response, Request& request) {
+        string filename = "www/";
+
+        string path = request.path_match[1];
+
+        // forbidden use `..` access content outside folder web/
+        size_t last_pos = path.rfind(".");
+        size_t current_pos = 0;
+        size_t pos;
+        while((pos=path.find('.', current_pos)) != string::npos && pos != last_pos) {
+            current_pos = pos;
+            path.erase(pos, 1);
+            last_pos--;
+        }
+
+        filename += path;
+        ifstream ifs;
+        // folder inspection across platform
+        if(filename.find('.') == string::npos) {
+            if(filename[filename.length()-1]!='/')
+                filename+='/';
+            filename += "index.html";
+        }
+        ifs.open(filename, ifstream::in);
+
+        if(ifs) {
+            ifs.seekg(0, ios::end);
+            size_t length=ifs.tellg();
+
+            ifs.seekg(0, ios::beg);
+
+            // copy file to response-stream , shouldn't use for large files
+            response << "HTTP/1.1 200 OK\r\nContent-Length: " << length << "\r\n\r\n" << ifs.rdbuf();
+
+            ifs.close();
+        } else {
+            // return unable to open if file doesn't exists
+            string content="Could not open file "+filename;
+            response << "HTTP/1.1 400 Bad Request\r\nContent-Length: " << content.length() << "\r\n\r\n" << content;
+        }
+    };
+
+    // start HTTP(S) server
+    server.start();
+}