Extended image checkings (#15)

* Extended image checks

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.4.0
+* ADD: isFileImage function was added for checking of files content-type
+* UPD: checkIsImageUrlAllowable function was renamed to isImageUrlAllowed and checks was extended
+
 ## 1.3.0
 * ADD: new module validationHelper and function checkIsImageUrlAllowable for checking of images URLs
 

karma.conf.js

@@ -63,6 +63,18 @@ module.exports = (config) => {
                 pattern: srcOriginalRecursivePath,
                 included: false,
                 served: true
+            },
+            {
+                pattern: 'test/images/*.+(png|jpg|gif|svg|bmp)',
+                watched: false,
+                included: false,
+                served: true
+            },
+            {
+                pattern: 'test/data/*.txt',
+                watched: false,
+                included: false,
+                served: true
             }
         ],
         preprocessors: {

lib/index.d.ts

@@ -62,7 +62,8 @@ declare module powerbi.extensibility.utils.dataview {
 }
 declare module powerbi.extensibility.utils.dataview {
     module validationHelper {
-        function checkIsImageUrlAllowable(url: string): boolean;
+        function isImageUrlAllowed(url: string): boolean;
+        function isFileImage(url: string, imageCheckResultCallBack: (isImage: boolean, contentType: string) => void): void;
     }
 }
 declare module powerbi.extensibility.utils.dataview {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "powerbi-visuals-utils-dataviewutils",
-  "version": "1.3.0",
+  "version": "1.4.0",
   "description": "dataviewutils",
   "main": "lib/index.js",
   "repository": {

src/validationHelper.ts

@@ -26,10 +26,30 @@
 
 module powerbi.extensibility.utils.dataview {
     export module validationHelper {
-        export function checkIsImageUrlAllowable(url: string): boolean {
-            // Excludes all URLs that don't contain .gif .jpg .png or .svg extensions.
-            // Also excludes directives "javascript:" and "data:".
-            return (/\.(gif|jpg|png|svg)$/i).test(url) && !(/(javascript:|data:)/i).test(url);
+        export function isImageUrlAllowed(url: string): boolean {
+            // Excludes all URLs that don't contain .gif .jpg .png or .svg extensions and don't start from "http(s)://".
+            // Base64 incoded images are allowable too.
+            return (/^https?:\/\/.+\.(gif|jpg|png|svg)$/i).test(url) || (/^data:image\/(gif|jpeg|png|svg\+xml);base64,/i).test(url);
+        }
+
+        export function isFileImage(url: string, imageCheckResultCallBack: (isImage: boolean, contentType: string) => void) {
+            let request = new XMLHttpRequest();
+            request.onreadystatechange = function () {
+                if (request.readyState !== this.HEADERS_RECEIVED) {
+                    return;
+                }
+
+                let contentType = request.getResponseHeader("Content-Type"),
+                supportedTypes = ["image/png", "image/jpeg", "image/gif", "image/svg+xml"];
+
+                if (supportedTypes.indexOf(contentType) > -1) {
+                    return imageCheckResultCallBack(true, contentType);
+                }
+
+                return imageCheckResultCallBack(false, contentType);
+            };
+            request.open("HEAD", url, true);
+            request.send();
         }
     }
 }

test/data/someplaintext.txt

@@ -0,0 +1 @@
+Plain text with some data that is used in unit tests