added parameters for cache key generation

Author: jayesbe

README.md

@@ -33,7 +33,7 @@ import CacheableImage from 'react-native-cacheable-image'
 
 * `activityIndicatorProps` - pass this property to alter the ActivityIndicator
 * `defaultSource`           - pass this property to provide a default source to fallback on (the defaultSource is attached to another CacheableImage component)
-
+* `useQueryParamsInCacheKey` - Defaults to false for backwards compatibility. Set to true to include query parameters in cache key generation. Set to an array of parameters to only include specific parameters in cache key generation. 
 
 ## Example
 

image.js

@@ -128,10 +128,21 @@ class CacheableImage extends React.Component {
             && source.hasOwnProperty('uri'))
         { // remote
             const url = new URL(source.uri, null, true);
+            
+            // handle query params for cache key
             let cacheable = url.pathname;
-            if (this.props.useQueryParamsInCacheKey) {
+            if (Array.isArray(this.props.useQueryParamsInCacheKey)) {
+                this.props.useQueryParamsInCacheKey.forEach(function(k) {
+                    if (url.query.hasOwnProperty(k)) {
+                        cacheable = cacheable.concat(url.query[k]);
+                    }    
+                });                
+            }
+            else if (this.props.useQueryParamsInCacheKey) {
                 cacheable = cacheable.concat(url.query);
             }
+            
+            // ignore extension
             // const type = url.pathname.replace(/.*\.(.*)/, '$1');
             const cacheKey = SHA1(cacheable); // +'.'+type;
 
@@ -212,7 +223,10 @@ class CacheableImage extends React.Component {
 CacheableImage.propTypes = {
     activityIndicatorProps: React.PropTypes.object,
     defaultSource: React.PropTypes.object,
-    useQueryParamsInCacheKey: React.PropTypes.bool
+    useQueryParamsInCacheKey: React.PropTypes.oneOfType([
+        React.PropTypes.bool,
+        React.PropTypes.array
+    ])
 };