get oeis files from API server

Author: ckrause

CHANGELOG.md

@@ -6,6 +6,10 @@ To install or update LODA, please follow the [installation instructions](https:/
 
 * Extend timeout for folder locking on Windows
 
+### Features
+
+* Retrieve OEIS files from cache on API server
+
 ## v22.1.9
 
 ### Bugfixes

src/api_client.cpp

@@ -63,6 +63,16 @@ void ApiClient::postCPUHour() {
   }
 }
 
+bool ApiClient::getOeisFile(const std::string& filename,
+                            const std::string& local_path) {
+  const std::string url = BASE_URL + "oeis/" + filename + ".gz";
+  const bool success = WebClient::get(url, local_path + ".gz", false, false);
+  if (success) {
+    gunzip(local_path + ".gz");
+  }
+  return success;
+}
+
 bool ApiClient::getProgram(int64_t index, const std::string& path) {
   std::remove(path.c_str());
   return WebClient::get(BASE_URL + "programs/" + std::to_string(index), path,
@@ -133,7 +143,6 @@ void ApiClient::updateSession() {
 }
 
 int64_t ApiClient::fetchInt(const std::string& endpoint) {
-  // TODO: store in tmp folder
   const std::string tmp = "tmp_int.txt";
   WebClient::get(BASE_URL + endpoint, tmp, true, true);
   std::ifstream in(tmp);

src/file.cpp

@@ -102,10 +102,10 @@ void gunzip(const std::string &path) {
     }
     // https://stackoverflow.com/questions/9964865/c-system-not-working-when-there-are-spaces-in-two-different-parameters
     execCmd("cmd /S /C \"\"" + program_files +
-            "\\Git\\usr\\bin\\gzip.exe\" -d \"" + path + "\"\"");
+            "\\Git\\usr\\bin\\gzip.exe\" -f -d \"" + path + "\"\"");
   }
 #else
-  execCmd("gzip -d \"" + path + "\"");
+  execCmd("gzip -f -d \"" + path + "\"");
 #endif
 }
 

src/include/api_client.hpp

@@ -14,6 +14,8 @@ class ApiClient {
 
   void postCPUHour();
 
+  bool getOeisFile(const std::string& filename, const std::string& local_path);
+
   Program getNextProgram();
 
  private:

src/oeis_manager.cpp

@@ -327,13 +327,13 @@ void OeisManager::update() {
     std::string cmd, path;
     for (auto &file : files) {
       path = Setup::getOeisHome() + file;
-      WebClient::get("https://oeis.org/" + file + ".gz", path + ".gz");
-      std::ifstream f(Setup::getOeisHome() + file);
-      if (f.good()) {
-        f.close();
-        std::remove(path.c_str());
+      ApiClient api_client;
+      if (!api_client.getOeisFile(file, path)) {
+        Log::get().warn("Cannot fetch " + file +
+                        ".gz from API server, falling back to OEIS");
+        WebClient::get("https://oeis.org/" + file + ".gz", path + ".gz");
+        gunzip(path + ".gz");
       }
-      gunzip(path + ".gz");
     }
     // update programs repository using git pull
     auto mode = Setup::getMiningMode();

src/oeis_sequence.cpp

@@ -4,6 +4,7 @@
 #include <iomanip>
 #include <sstream>
 
+#include "api_client.hpp"
 #include "big_number.hpp"
 #include "file.hpp"
 #include "parser.hpp"
@@ -210,7 +211,12 @@ Sequence OeisSequence::getTerms(int64_t max_num_terms) const {
           big_file.peek() == std::ifstream::traits_type::eof()) {
         ensureDir(path);
         std::remove(path.c_str());
-        WebClient::get(url_str() + "/" + id_str("b") + ".txt", path);
+        ApiClient api_client;
+        if (!api_client.getOeisFile(id_str("b") + ".txt", path)) {
+          Log::get().warn(
+              "Cannot fetch b-file from API server, falling back to OEIS");
+          WebClient::get(url_str() + "/" + id_str("b") + ".txt", path);
+        }
         big = loadBFile(id, terms);
       }
     }