From 72d4c19e6c7c3d71a3025a07adb350ada3a1c859 Mon Sep 17 00:00:00 2001
From: Maneesh P M <manu.pm55@gmail.com>
Date: Sun, 25 Jul 2021 12:24:44 +0530
Subject: [PATCH] Allow kiwix-serve to get suggestions of custom range

This will allow handle_suggest API to accept two arguments `start` and
`suggestionLength` that will allow handle_suggest to retrieve
suggestions in the given range rather than the default 0-10 range.
---
 src/server/internalServer.cpp | 24 +++++++++----
 test/server.cpp               | 64 +++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/src/server/internalServer.cpp b/src/server/internalServer.cpp
index 957b128f8..ec8761068 100644
--- a/src/server/internalServer.cpp
+++ b/src/server/internalServer.cpp
@@ -334,7 +334,7 @@ std::unique_ptr<Response> InternalServer::build_homepage(const RequestContext& r
 
 // TODO: retrieve searcher from caching mechanism
 SuggestionsList_t getSuggestions(const zim::Archive* const archive,
-                  const std::string& queryString, int suggestionCount)
+                  const std::string& queryString, int start, int suggestionCount)
 {
   SuggestionsList_t suggestions;
   if (archive->hasTitleIndex()) {
@@ -342,8 +342,7 @@ SuggestionsList_t getSuggestions(const zim::Archive* const archive,
     zim::Query suggestionQuery;
     suggestionQuery.setQuery(queryString, true);
     auto suggestionSearch = searcher.search(suggestionQuery);
-    auto suggestionResult = suggestionSearch.getResults(0, suggestionCount);
-
+    auto suggestionResult = suggestionSearch.getResults(start, suggestionCount);
     for (auto it = suggestionResult.begin(); it != suggestionResult.end(); it++) {
       SuggestionItem suggestion(it.getTitle(), kiwix::normalize(it.getTitle()),
                                 it.getPath(), it.getSnippet());
@@ -426,8 +425,6 @@ std::unique_ptr<Response> InternalServer::handle_suggest(const RequestContext& r
 
   std::string content;
   std::string mimeType;
-  unsigned int maxSuggestionCount = 10;
-  unsigned int suggestionCount = 0;
 
   std::string bookName;
   std::string bookId;
@@ -442,6 +439,20 @@ std::unique_ptr<Response> InternalServer::handle_suggest(const RequestContext& r
     return Response::build_404(*this, request, bookName, "");
   }
 
+  auto start = 0;
+  try {
+    start = request.get_argument<unsigned int>("start");
+  } catch (const std::exception&) {}
+
+  unsigned int suggestionLength = 10;
+  try {
+    suggestionLength = request.get_argument<unsigned int>("suggestionLength");
+  } catch (const std::exception&) {}
+
+  if (suggestionLength == 0) {
+    suggestionLength = 10;
+  }
+
   if (archive == nullptr) {
     return Response::build_404(*this, request, bookName, "");
   }
@@ -455,7 +466,7 @@ std::unique_ptr<Response> InternalServer::handle_suggest(const RequestContext& r
   bool first = true;
 
   /* Get the suggestions */
-  SuggestionsList_t suggestions = getSuggestions(archive.get(), queryString, maxSuggestionCount);
+  SuggestionsList_t suggestions = getSuggestions(archive.get(), queryString, start, suggestionLength);
   for(auto& suggestion:suggestions) {
     MustacheData result;
     result.set("label", suggestion.getTitle());
@@ -470,7 +481,6 @@ std::unique_ptr<Response> InternalServer::handle_suggest(const RequestContext& r
     result.set("first", first);
     first = false;
     results.push_back(result);
-    suggestionCount++;
   }
 
 
diff --git a/test/server.cpp b/test/server.cpp
index f900cd938..ecc2015e4 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -1168,3 +1168,67 @@ TEST_F(LibraryServerTest, catalog_v2_entries_filtered_by_search_terms)
     "</feed>\n"
   );
 }
+
+TEST_F(LibraryServerTest, suggestions_in_range)
+{
+  /**
+   * Attempt to get 50 suggestions in steps of 5
+   * The suggestions are returned in the json format
+   * [{sugg1}, {sugg2}, ... , {suggN}, {suggest ft search}]
+   * Assuming the number of suggestions = (occurance of "{" - 1)
+   */
+  {
+    int suggCount = 0;
+    for (int i = 0; i < 10; i++) {
+      std::string url = "/suggest?content=zimfile&term=ray&start=" + std::to_string(i*5) + "&suggestionLength=5";
+      const auto r = zfs1_->GET(url.c_str());
+      std::string body = r->body;
+      int currCount = std::count(body.begin(), body.end(), '{') - 1;
+      ASSERT_EQ(currCount, 5);
+      suggCount += currCount;
+    }
+    ASSERT_EQ(suggCount, 50);
+  }
+
+  // Attempt to get 10 suggestions in steps of 5 even though there are only 8
+  {
+    std::string url = "/suggest?content=zimfile&term=song+for+you&start=0&suggestionLength=5";
+    const auto r1 = zfs1_->GET(url.c_str());
+    std::string body = r1->body;
+    int currCount = std::count(body.begin(), body.end(), '{') - 1;
+    ASSERT_EQ(currCount, 5);
+
+    url = "/suggest?content=zimfile&term=song+for+you&start=5&suggestionLength=5";
+    const auto r2 = zfs1_->GET(url.c_str());
+    body = r2->body;
+    currCount = std::count(body.begin(), body.end(), '{') - 1;
+    ASSERT_EQ(currCount, 3);
+  }
+
+  // Attempt to get 10 suggestions even though there is only 1
+  {
+    std::string url = "/suggest?content=zimfile&term=strong&start=0&suggestionLength=5";
+    const auto r = zfs1_->GET(url.c_str());
+    std::string body = r->body;
+    int currCount = std::count(body.begin(), body.end(), '{') - 1;
+    ASSERT_EQ(currCount, 1);
+  }
+
+  // No Suggestion
+  {
+    std::string url = "/suggest?content=zimfile&term=oops&start=0&suggestionLength=5";
+    const auto r = zfs1_->GET(url.c_str());
+    std::string body = r->body;
+    int currCount = std::count(body.begin(), body.end(), '{') - 1;
+    ASSERT_EQ(currCount, 0);
+  }
+
+  // Out of bound value
+  {
+    std::string url = "/suggest?content=zimfile&term=ray&start=-2&suggestionLength=-1";
+    const auto r = zfs1_->GET(url.c_str());
+    std::string body = r->body;
+    int currCount = std::count(body.begin(), body.end(), '{') - 1;
+    ASSERT_EQ(currCount, 0);
+  }
+}
\ No newline at end of file