Added image pre-fetching

README.md

@@ -165,3 +165,20 @@ Default cache purge time can be specified in number of days.
 
 
 **for android, you need to initialize in the application onlaunch event before clearing the cache**
+
+### Prefetching images
+
+It is possible to prefetch images so that they are already loaded in the cache before use.
+
+```
+let urls = [
+  url1,
+  url2
+]
+
+preFetchImage(urls)
+.then(() => { console.log('prefetch success!'); })
+.catch((error) => { console.error('prefetch error: '+error); });
+```
+
+** note: on iOS calling preFetchImage multiple times before the promise resolves will cancel previous calls

index.d.ts

@@ -47,3 +47,9 @@ export function initializeOnAngular(): void;
  * @param days : limit of the cache
  */
 export function setCacheLimit(days: number): void;
+
+/**
+ * To prefetch images to allow loading before using the images
+ * @param days : array of URLs to prefetch
+ */
+export function preFetchImage(urls:Array<string>) : Promise<void>;

ios-ts-lib/helpers.ts

@@ -77,7 +77,7 @@ export class Helpers {
   public static getPlaceholderUIImage(value) {
     if (types.isString(value)) {
       if (utils.isFileOrResourcePath(value)) {
-        return imageSource.fromFileOrResource(value).ios;
+        return imageSource.ImageSource.fromFileOrResourceSync(value).ios;
       }
     }
 

package.json

@@ -1,28 +1,4 @@
 {
-  "_from": "nativescript-web-image-cache",
-  "_id": "[email protected]",
-  "_inBundle": false,
-  "_integrity": "sha512-zIFzI09vBuQcODCdxuDgtBWmtTxNSxm06win+IU7t2zblk2ItdGawDbwd0ZLX9RN+moUf/ytTj+MMoBgowdt6Q==",
-  "_location": "/nativescript-web-image-cache",
-  "_phantomChildren": {},
-  "_requested": {
-    "type": "tag",
-    "registry": true,
-    "raw": "nativescript-web-image-cache",
-    "name": "nativescript-web-image-cache",
-    "escapedName": "nativescript-web-image-cache",
-    "rawSpec": "",
-    "saveSpec": null,
-    "fetchSpec": "latest"
-  },
-  "_requiredBy": [
-    "#USER",
-    "/"
-  ],
-  "_resolved": "https://registry.npmjs.org/nativescript-web-image-cache/-/nativescript-web-image-cache-4.2.4.tgz",
-  "_shasum": "acc14c6684fc2dd7481a66f1f01a98b00e1ce62d",
-  "_spec": "nativescript-web-image-cache",
-  "_where": "/Users/Sumeet/smg/gudds/NKY/ns/sample",
   "author": {
     "name": "Batheja Sumeet"
   },
@@ -61,7 +37,9 @@
     "type": "git",
     "url": "git+https://github.com/VideoSpike/nativescript-web-image-cache.git"
   },
-  "scripts": {},
+  "scripts": {
+    "build": "./node_modules/.bin/tsc"
+  },
   "typings": "web-image-cache.d.ts",
   "version": "5.0.0"
 }

platforms/android/include.gradle

@@ -1,13 +1,9 @@
 /* Include.gradle configuration: http://docs.nativescript.org/plugins/plugins#includegradle-specification */
 
 android {
-	productFlavors {
-		"nativescript-web-image-cache" {
-			dimension "nativescript-web-image-cache"
-		}
-	}
+
 }
 
 dependencies {
-	compile "com.facebook.fresco:fresco:1.10.0"
+	compile "com.facebook.fresco:fresco:2.3.0"
 }

platforms/ios/Podfile

@@ -1 +1 @@
-pod 'SDWebImage', '~> 4.4.1'
+pod 'SDWebImage', '~> 5.9.4'

types/fresco.d.ts

@@ -1,12 +1,20 @@
 declare namespace com {
   export namespace facebook {
     export namespace datasource {
+      export class BaseDataSubscriber {
+        public static extend(param: any);
+      }
       export class DataSource { }
     }
     export namespace common {
       export namespace references {
         export class CloseableReference { }
       }
+      export namespace executors {
+        export class UiThreadImmediateExecutorService {
+          public static getInstance() : any;
+        }
+      }
       export namespace internal {
         export class Supplier { }
       }
@@ -18,7 +26,9 @@ declare namespace com {
         export class ImagePipeline { }
       }
       export namespace request {
-        export class ImageRequest { }
+        export class ImageRequest {
+          public static fromUri(param0: any): any;
+        }
       }
       export namespace image {
         export class ImageInfo { }

web-image-cache.android.d.ts

@@ -13,3 +13,4 @@ export declare function setCacheLimit(numberOfDays: any): void;
 export declare function initialize(): void;
 export declare function clearCache(): void;
 export declare function initializeOnAngular(): void;
+export declare function preFetchImage(urls: Array<string>): Promise<void>;

web-image-cache.android.ts

@@ -175,3 +175,43 @@ export function clearCache() {
 export function initializeOnAngular() {
   throw new Error("'initializeOnAngular' has been removed from 'nativescript-web-image-cache', see its readme for details!");
 }
+
+export function preFetchImage(urls: Array<string>) : Promise<void> {
+  return new Promise<void>((resolve, reject) => {
+    if (!urls || !Array.isArray(urls) || urls.length<1) {
+      reject(`preFetchImage: param should be array of urls`);
+    } else {
+      let counter:number=0;
+
+      urls.forEach((url) => {
+        const uri = android.net.Uri.parse(url);
+        const prefetchSubscriber = com.facebook.datasource.BaseDataSubscriber.extend({
+          onNewResultImpl(dataSource) {
+            counter++;
+            if (counter===urls.length) { resolve(); }
+          },
+          onFailureImpl(dataSource) {
+            counter++;
+            if (counter===urls.length) {
+              reject(`preFetchImage: failed to prefetch ${uri.toString()}`);
+            }
+          }
+        });
+
+        /*
+          prefetchToDiskCache() --> load to disk slower but less CPU
+          prefetchToBitmapCache --> load to memory cache, faster but more CPU
+        */
+        let dataSource = com.facebook.drawee.backends.pipeline.Fresco.getImagePipeline().prefetchToBitmapCache(
+          com.facebook.imagepipeline.request.ImageRequest.fromUri(uri),
+          application.android.context
+        );
+
+        dataSource.subscribe(
+          new prefetchSubscriber(),
+          com.facebook.common.executors.UiThreadImmediateExecutorService.getInstance()
+        );
+      });
+    }
+  });
+}

web-image-cache.ios.d.ts

@@ -13,3 +13,4 @@ export declare class WebImage extends WebImageCommon {
 export declare function setCacheLimit(numberOfDays: any): void;
 export declare function clearCache(): void;
 export declare function initializeOnAngular(): void;
+export declare function preFetchImage(urls: Array<string>): Promise<void>;