Catch non-targeted spam.

src/cgi.cpp

@@ -61,6 +61,13 @@ entry_type parse_formdata()
     entry_type entry;
 
     cgicc::Cgicc cgi;
+
+    // Catch non-targeted spam.
+    if (!cgi("url").empty())
+    {
+        throw SpamException{};
+    }
+
     entry.instance = cgi("instance");
     entry.tags = string_to_vector(cgi("tags"));
     transform(entry.tags.begin(), entry.tags.end(), entry.tags.begin(),
@@ -176,4 +183,10 @@ string text2html(string text)
 
     return text;
 }
+
 } // namespace FediBlock::cgi
+
+const char *SpamException::what() const noexcept
+{
+    return "Spam detected.";
+}

src/cgi.hpp

@@ -1,5 +1,5 @@
 /*  This file is part of FediBlock-backend.
- *  Copyright © 2020 tastytea <tastytea@tastytea.de>
+ *  Copyright © 2020, 2021 tastytea <tastytea@tastytea.de>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Affero General Public License as published by
@@ -19,6 +19,7 @@
 
 #include "types.hpp"
 
+#include <exception>
 #include <string>
 #include <string_view>
 #include <vector>
@@ -53,4 +54,11 @@ string text2html(string text);
 
 } // namespace FediBlock::cgi
 
+class SpamException : public std::exception
+{
+public:
+    // NOLINTNEXTLINE(modernize-use-nodiscard)
+    const char *what() const noexcept override;
+};
+
 #endif // FEDIBLOCK_BACKEND_CGI_HPP

src/main.cpp

@@ -1,5 +1,5 @@
 /*  This file is part of FediBlock-backend.
- *  Copyright © 2020 tastytea <tastytea@tastytea.de>
+ *  Copyright © 2020, 2021 tastytea <tastytea@tastytea.de>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Affero General Public License as published by
@@ -79,6 +79,11 @@ int main()
 
         files::remove_tmpdir();
     }
+    catch (const SpamException &e)
+    {
+        cerr << e.what() << '\n';
+        cout << e.what() << "\r\n";
+    }
     catch (const exception &e)
     {
         cerr << e.what() << '\n';