Generate hashtable

src/hash.cpp

@@ -0,0 +1,80 @@
+/*  This file is part of libravatarserv.
+ *  Copyright © 2022 tastytea <tastytea@tastytea.de>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hash.hpp"
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <string_view>
+
+#define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1 // necessary for MD5
+#include <cryptopp/cryptlib.h>
+#include <cryptopp/filters.h>
+#include <cryptopp/hex.h>
+#include <cryptopp/md5.h>
+#include <cryptopp/sha.h>
+
+namespace libravatarserv::hash {
+
+std::string generate_hash(const algorithm algo, const std::string_view text) {
+    using namespace CryptoPP;
+
+    SHA256 sha256;
+    Weak::MD5 md5;
+    std::unique_ptr<HashTransformation> algo_to_use{&sha256};
+    if (algo == algorithm::MD5) {
+        algo_to_use.reset(&md5);
+    }
+
+    std::string hash;
+    StringSource s(text.data(), true,
+                   new HashFilter(*algo_to_use,
+                                  new HexEncoder(new StringSink(hash))));
+    std::transform(hash.begin(), hash.end(), hash.begin(), ::tolower);
+
+    return hash;
+}
+
+table generate_table(const algorithm algo, const fs::path &directory) {
+    table hashtable;
+    for (const fs::path &path : fs::recursive_directory_iterator(directory)) {
+        if (fs::is_regular_file(path)) {
+            std::string email = path.filename();
+            std::transform(email.begin(), email.end(), email.begin(),
+                           ::tolower);
+            hashtable.insert({generate_hash(algo, email), email});
+        }
+    }
+
+    return hashtable;
+}
+
+bool is_valid(const std::string_view hash) {
+    auto not_hex{[](const char c) {
+        if (c >= 0x61 && c <= 0x66) { // a-f
+            return false;
+        }
+        if (c >= 0x30 && c <= 0x39) { // 0-9
+            return false;
+        }
+        return true;
+    }};
+
+    return !std::any_of(hash.begin(), hash.end(), not_hex);
+}
+
+} // namespace libravatarserv::hash

src/hash.hpp

@@ -0,0 +1,46 @@
+/*  This file is part of libravatarserv.
+ *  Copyright © 2022 tastytea <tastytea@tastytea.de>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LIBRAVATARSERV_HASH_HPP
+#define LIBRAVATARSERV_HASH_HPP
+
+#include "fs-compat.hpp"
+
+#include <map>
+#include <string>
+#include <string_view>
+
+namespace libravatarserv::hash {
+
+enum class algorithm {
+    SHA256,
+    MD5
+};
+
+using table = std::map<std::string, std::string>;
+
+// generate hash from text
+[[nodiscard]] std::string generate_hash(algorithm algo, std::string_view text);
+
+// generate hash -> email table
+[[nodiscard]] table generate_table(algorithm algo, const fs::path &directory);
+
+// return false if invalid characters are found in hash
+[[nodiscard]] bool is_valid(std::string_view hash);
+
+} // namespace libravatarserv::hash
+
+#endif // LIBRAVATARSERV_HASH_HPP

src/main.cpp

@@ -15,6 +15,7 @@
  */
 
 #include "config.hpp"
+#include "hash.hpp"
 #include "helpers.hpp"
 #include "request.hpp"
 #include "version.hpp"
@@ -44,6 +45,7 @@ int main(int /*argc*/, char * /*argv*/[]) {
         }
         std::cout << "  HASH: " << req.hash << "\n  SIZE: " << req.size
                   << "\n  FALLBACK: " << req.fallback << '\n';
+        const auto hashtable{hash::generate_table(req.algo, cfg.avatar_dir)};
 
     } catch (const std::runtime_error &e) {
         if (std::strlen(e.what()) != 0) {

src/request.cpp

@@ -16,6 +16,8 @@
 
 #include "request.hpp"
 
+#include "hash.hpp"
+
 #include <algorithm>
 #include <cstdint>
 #include <iostream>
@@ -44,6 +46,15 @@ request parse(const std::string_view uri) {
     std::transform(uri.begin() + offset, uri.begin() + pos, req.hash.begin(),
                    ::tolower);
 
+    if (req.hash.size() == 64 && hash::is_valid(req.hash)) {
+        req.algo = hash::algorithm::SHA256;
+    } else if (req.hash.size() == 32 && hash::is_valid(req.hash)) {
+        req.algo = hash::algorithm::MD5;
+    } else {
+        std::cout << "Status: 400 Bad Request\n\n";
+        throw std::runtime_error{"Invalid hash"};
+    }
+
     if (pos != uri.size()) {
         std::string uri_rest;
         uri_rest.resize(uri.size() - pos);

src/request.hpp

@@ -17,6 +17,8 @@
 #ifndef LIBRAVATARSERV_REQUEST_HPP
 #define LIBRAVATARSERV_REQUEST_HPP
 
+#include "hash.hpp"
+
 #include <cstdint>
 #include <string>
 #include <string_view>
@@ -25,12 +27,15 @@ namespace libravatarserv::request {
 
 struct request {
     std::string hash;
+    hash::algorithm algo;
     std::int16_t size;
     std::string fallback;
 };
 
+// parse request and return results
 [[nodiscard]] request parse(std::string_view uri);
 
+// get one parameter from an URI
 [[nodiscard]] std::string_view get_parameter(std::string_view uri,
                                              const std::string &parameter);