Warning on forms with passwords

server/Ksp.WebServer/.vscode/launch.json

@@ -0,0 +1,34 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": ".NET Core Launch (web)",
+            "type": "coreclr",
+            "request": "launch",
+            "preLaunchTask": "build",
+            "program": "${workspaceFolder}/bin/Debug/netcoreapp3.1/Ksp.WebServer.dll",
+            "args": [],
+            "cwd": "${workspaceFolder}",
+            "stopAtEntry": false,
+            "serverReadyAction": {
+                "action": "openExternally",
+                "pattern": "\\bNow listening on:\\s+(https?://\\S+)"
+            },
+            "env": {
+                "ASPNETCORE_ENVIRONMENT": "Development"
+            },
+            "sourceFileMap": {
+                "/Views": "${workspaceFolder}/Views"
+            }
+        },
+        {
+            "name": ".NET Core Attach",
+            "type": "coreclr",
+            "request": "attach",
+            "processId": "${command:pickProcess}"
+        }
+    ]
+}

server/Ksp.WebServer/.vscode/tasks.json

@@ -0,0 +1,42 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "build",
+            "command": "dotnet",
+            "type": "process",
+            "args": [
+                "build",
+                "${workspaceFolder}/Ksp.WebServer.csproj",
+                "/property:GenerateFullPaths=true",
+                "/consoleloggerparameters:NoSummary"
+            ],
+            "problemMatcher": "$msCompile"
+        },
+        {
+            "label": "publish",
+            "command": "dotnet",
+            "type": "process",
+            "args": [
+                "publish",
+                "${workspaceFolder}/Ksp.WebServer.csproj",
+                "/property:GenerateFullPaths=true",
+                "/consoleloggerparameters:NoSummary"
+            ],
+            "problemMatcher": "$msCompile"
+        },
+        {
+            "label": "watch",
+            "command": "dotnet",
+            "type": "process",
+            "args": [
+                "watch",
+                "run",
+                "${workspaceFolder}/Ksp.WebServer.csproj",
+                "/property:GenerateFullPaths=true",
+                "/consoleloggerparameters:NoSummary"
+            ],
+            "problemMatcher": "$msCompile"
+        }
+    ]
+}

server/Ksp.WebServer/KspPageRewriter.cs

@@ -0,0 +1,32 @@
+using System.IO;
+using AngleSharp.Html;
+using Microsoft.AspNetCore.Http;
+
+namespace Ksp.WebServer
+{
+    public class KspPageRewriter
+    {
+        public string RewriteHtml(string source, HttpContext context)
+        {
+            var p = new AngleSharp.Html.Parser.HtmlParser();
+            var document = p.ParseDocument(source);
+
+            foreach (var form in document.QuerySelectorAll("form"))
+            {
+                if (form.QuerySelector("input[type=password]") is null)
+                    continue;
+
+                var warning = document.CreateElement("div");
+                warning.SetAttribute("style", "color: red; font-size: 3em; font-weight: bold");
+                warning.TextContent = "Web běží na magické proxy, které byste měli věřit!!!";
+                form.Prepend(warning);
+            }
+
+
+
+            var outputHtml = new StringWriter();
+            document.ToHtml(outputHtml, new PrettyMarkupFormatter() { Indentation = "\t", NewLine = "\n" });
+            return outputHtml.ToString();
+        }
+    }
+}

server/Ksp.WebServer/Startup.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
+using System.Text;
 using System.Threading.Tasks;
 using AspNetCore.Proxy;
 using AspNetCore.Proxy.Builders;
@@ -39,15 +40,17 @@ namespace Ksp.WebServer
                 .ConfigurePrimaryHttpMessageHandler(h => {
                 return new HttpClientHandler {
                     AllowAutoRedirect = false,
-                    UseCookies = false
+                    UseCookies = false,
+                    AutomaticDecompression = DecompressionMethods.All
                 };
             });
             services.AddProxies();
             services.Configure<KspProxyConfig>(Configuration.GetSection(nameof(KspProxyConfig)));
+            services.AddSingleton<KspPageRewriter>();
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
-        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IOptions<KspProxyConfig> kspProxyConfig)
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IOptions<KspProxyConfig> kspProxyConfig, KspPageRewriter pageRewriter)
         {
             Console.WriteLine($"Running {env.EnvironmentName} env, root={env.ContentRootPath}, host={kspProxyConfig.Value.Host}");
 
@@ -97,7 +100,7 @@ namespace Ksp.WebServer
                         // Console.WriteLine(request);
                         return Task.CompletedTask;
                     });
-                    opt.WithAfterReceive((cx, response) => {
+                    opt.WithAfterReceive(async (cx, response) => {
                         // Console.WriteLine(response);
                         if (response.Headers.Location is object && response.Headers.Location.Host == baseUri.Host)
                         {
@@ -115,7 +118,13 @@ namespace Ksp.WebServer
                                  .Replace($"; domain={baseUri.Host}", $"; domain={cx.Request.Host.Host}")
                             ));
                         }
-                        return Task.CompletedTask;
+
+                        if (new [] { "text/html", "application/xhtml+xml" }.Contains(response.Content.Headers.ContentType.MediaType))
+                        {
+                            var str = await response.Content.ReadAsStringAsync();
+                            str = pageRewriter.RewriteHtml(str, cx);
+                            response.Content = new StringContent(str, Encoding.UTF8, "text/html");
+                        }
                     });
                 }));
         }