fix: Support {{cur}} for custom URL's, keep Unsplash link back hidd…

…en if using custom URL

README.md

@@ -50,7 +50,7 @@ __NOTE__: PHP cURL is required for fetching external images.
 __NOTE__: There [have been reports](https://github.com/tomershvueli/homepage/issues/24#issuecomment-754450034) that applying for a Normal API upgrading from a demo API will result in Unsplash shutting down your API key entirely. I suggest sticking to the demo API key and setting the `time_to_refresh_bg` config variable to `90000`. This will ensure that you don't surpass the 50 hourly requests that Unsplash provides for demo API keys. Or feel free to use a custom background image (see below). 
 
 ### Custom Background Images
-- `custom_url` => Input a custom URL that will return proper JSON
+- `custom_url` => Input a custom URL that will return proper JSON. Supports `{{cur}}` substitution for current URL. 
 - `custom_url_headers` => Add any headers that may be needed to complete a cURL request to the aforementioned URL properly
 - `custom_url_selector` => Input a proper PHP array selector to be used on the JSON received above. For example, if I were to fetch from Github's user API with a 'custom_url' of 'https://api.github.com/users/octocat', the 'custom_url_selector' would simply be `['avatar_url']`. `[{random}]` can be replaced for a random index in an array. 
 

src/hp_assets/js/main.js

@@ -62,8 +62,10 @@ function setBgImg() {
       if (bg != "" && bg != null) {
         preloadimages([bg]).done(function(images) {
           $("#homepage").css("background-image", `url(${bg})`).css("background-size", "cover");
-          $("#pic-info-wrap").removeClass("hidden");
-          $("#pic-info-url").attr("href", `${data['image_user_url']}${unsplashUtmPostfix}`).text(data['image_user_name']);
+          if (data['image_user_name']) {
+            $("#pic-info-wrap").removeClass("hidden");
+            $("#pic-info-url").attr("href", `${data['image_user_url']}${unsplashUtmPostfix}`).text(data['image_user_name']);
+          }
         });
       }
     }

src/hp_assets/lib/ajax_get_image.php

@@ -42,12 +42,19 @@ function traverse_json($json, $selector) {
     return $obj;
   }
 
+  function get_current_url() {
+    $protocol = ((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off') || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
+    $domainName = $_SERVER['SERVER_NAME'];
+    return $protocol . $domainName;
+  }
+
   $config = json_decode(file_get_contents(dirname(__FILE__) . "/../../config.json"), true);
 
   if (!empty($config['protected']['custom_url'])) {
     // We're fetching from a custom URL
-    $json      = json_decode(curl_get_contents($config['protected']['custom_url'], $config['protected']['custom_url_headers']), true);
-    $image_url = traverse_json($json, $config['protected']['custom_url_selector']);
+    $custom_url = str_replace("{{cur}}", get_current_url(), $config['protected']['custom_url']);
+    $json       = json_decode(curl_get_contents($custom_url, $config['protected']['custom_url_headers']), true);
+    $image_url  = traverse_json($json, $config['protected']['custom_url_selector']);
 
     echo json_encode(array('success' => 1, 'url' => $image_url));
   } else if (!empty($config['protected']['unsplash_client_id'])) {