From 6347de2635e70daf85d273dfee27e91079fa8d82 Mon Sep 17 00:00:00 2001
From: Joshua Ramon Enslin <joshua@museum-digital.de>
Date: Sat, 5 Mar 2022 13:58:18 +0100
Subject: [PATCH] Validate Wikidata IDs before attempting to fetch from
 Wikidata

Close #8
---
 src/NodaWikidataFetcher.php | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/NodaWikidataFetcher.php b/src/NodaWikidataFetcher.php
index f742054..7bdec52 100644
--- a/src/NodaWikidataFetcher.php
+++ b/src/NodaWikidataFetcher.php
@@ -86,6 +86,26 @@ final class NodaWikidataFetcher {
     /** @var MDMysqli */
     private MDMysqli $_mysqli_noda;
 
+    /**
+     * Validates a Wikidata ID. A Wikidata ID must start with a capital Q and be
+     * numeric otherwise.
+     *
+     * @param string $wikidata_id Input ID to validate.
+     *
+     * @return void
+     */
+    public static function validateWikidataId(string $wikidata_id):void {
+
+        if (substr($wikidata_id, 0, 1) !== 'Q') {
+            throw new MDgenericInvalidInputsException("Wikidata IDs start with Q");
+        }
+
+        if (!is_numeric(substr($wikidata_id, 1))) {
+            throw new MDgenericInvalidInputsException("Wikidata IDs are numeric following the Q");
+        }
+
+    }
+
     /**
      * Attempts to fetch a Wikidata ID from a provided URL.
      *
@@ -714,6 +734,8 @@ final class NodaWikidataFetcher {
      */
     public function retrievePersinstInfoFromWikidataID(string $lang, string $wikidata_id, int $persinst_id, string $erfasst_von) {
 
+        self::validateWikidataId($wikidata_id);
+
         $data = json_decode(MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . $wikidata_id . ".json", 10000), true);
         if ($data === null) {
             throw new MDhttpFailedException("Failed fetching from Wikidata. Try again later.");
@@ -1054,6 +1076,8 @@ final class NodaWikidataFetcher {
      */
     public function retrievePlaceInfoFromWikidataID(string $lang, string $wikidata_id, int $onum, string $erfasst_von) {
 
+        self::validateWikidataId($wikidata_id);
+
         $data = MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . urlencode($wikidata_id) . ".json", 10000);
         if (!$data = json_decode($data, true)) {
             throw new MDhttpFailedException("Failed fetching from Wikidata. Try again later.");
@@ -1455,6 +1479,8 @@ final class NodaWikidataFetcher {
      */
     public function retrieveTagInfoFromWikidataID(string $lang, string $wikidata_id, int $tag_id, string $erfasst_von) {
 
+        self::validateWikidataId($wikidata_id);
+
         $data = MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . $wikidata_id . ".json", 10000);
         $data = json_decode($data, true);
         if ($data === null) {