IOS分享擴展使用JS腳本

實現一個分享擴展插件，功能是從Safari網頁中截取當前網頁的圖片內容

基本的步驟總結在下面：

1.創建一個JS文件，命名爲MyJavascriptFile.js，文件的功能是解析safari網頁內容，獲取到網頁中的所有圖片節點，解析從圖片的URL，返回所有圖片URL拼接而成的字符串。
JS中主要用到run: function(arguments){}這個方法來處理抓取數據的邏輯，處理抓取到的數據調用 arguments.completionFunction({ "webImages": imageArrStr }); 這個方法把數據返回，"webImages"這個key可以自定義，在第三步的原生層OC代碼中需要用到這個key把JS層抓取到的數據取出來，然後可以對這些圖片數據進行保存、上傳等需要的操作了。

MyJavascriptFile.js文件內容

var BuscapeClass = function() {};

BuscapeClass.prototype = {
    
    run: function(arguments) {
        var imageArray = new Array();
        var objs = document.getElementsByTagName("img");
        for(var i=0;i<objs.length;i++){
            if(imageArray.indexOf(objs[i].src) == -1){
                imageArray.push(objs[i].src);
            }
        }
        var imageArrStr = imageArray.join('+');
        // Pass the baseURI of the webpage to the extension.
        arguments.completionFunction({ "webImages": imageArrStr });
    },
    
    // Note that the finalize function is only available in iOS.
    finalize: function(arguments) {
        // arguments contains the value the extension provides in [NSExtensionContext completeRequestReturningItems:completion:].
        // In this example, the extension provides a color as a returning item.
        // document.body.style.backgroundColor = arguments["bgColor"];
        
        var bestOffer = arguments["bestOffer"];
        
        alert("A melhor oferta é da loja\n" + bestOffer["sellername"] + " por " + bestOffer["price"]);
    }
};

// The JavaScript file must contain a global object named "ExtensionPreprocessingJS".
var ExtensionPreprocessingJS = new BuscapeClass;

2.在info.plis文件中把創建的JS文件進行配置，配置如下：
配置的源碼

	<key>NSExtension</key>
	<dict>
		<key>NSExtensionAttributes</key>
		<dict>
			<key>NSExtensionActivationRule</key>
			<string>SUBQUERY (
    extensionItems,
    $extensionItem,
    SUBQUERY (
        $extensionItem.attachments,
        $attachment,
        (
       		 	ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.url"
       		 || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.image"
       		 || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.plain-text"
        )
        
    ).@count >= $extensionItem.attachments.@count
).@count >= 1</string>
			<key>NSExtensionJavaScriptPreprocessingFile</key>
			<string>MyJavascriptFile</string>
		</dict>
		<key>NSExtensionMainStoryboard</key>
		<string>MainInterface</string>
		<key>NSExtensionPointIdentifier</key>
		<string>com.apple.share-services</string>
	</dict>

3.原生層OC代碼中處理JS抓取的數據，主要用到這兩句，把數據取出來"webImages"這個key要和JS中定義的KEY一致

NSDictionary *results = jsDict[NSExtensionJavaScriptPreprocessingResultsKey];
NSString* result = [results objectForKey:@"webImages"];

完整的處理代碼

- (void)fetchDataFromWebContent {
    __weak typeof(self) weakSelf = self;

    //獲取inputItems，在這裏itemProvider是你要分享的圖片
    NSArray* extensionItems = self.extensionContext.inputItems;
    for (NSExtensionItem *extensionItem in extensionItems) {
        
        NSMutableArray* tmpTypeImageArr = [NSMutableArray array];
        NSMutableArray* tmpTypePropertyListArr = [NSMutableArray array];
        
        NSArray* attachments = extensionItem.attachments;
        // 處理attachments
        for (NSItemProvider *itemProvider in attachments) {
            
            // 注入JS獲取圖片數據數據
            if ([itemProvider hasItemConformingToTypeIdentifier:(NSString *)kUTTypePropertyList]) {
                [itemProvider loadItemForTypeIdentifier:(NSString *)kUTTypePropertyList options:nil completionHandler:^(NSDictionary *jsDict, NSError *error) {
                    NSLog(@"jsDict: %@", jsDict);
                    
                    dispatch_async(dispatch_get_main_queue(), ^{
                        // Get javascript result
                        NSDictionary *results = jsDict[NSExtensionJavaScriptPreprocessingResultsKey];
                        NSString* result = [results objectForKey:@"webImages"];
                        BMLog(@"=== webImages ===%@", result);
                        NSArray* tmpArr = [weakSelf handleImages:result];
                        if (tmpArr.count > 0) {
                            [tmpTypePropertyListArr addObjectsFromArray:tmpArr];
                        }
                        
                        [weakSelf handleResult:tmpTypePropertyListArr];
                    });
                }];
            }
        }
    }
}

- (NSArray*)handleImages:(NSString*)imagesStr {
    NSMutableArray* mUrlArray = [NSMutableArray arrayWithArray:[imagesStr componentsSeparatedByString:@"+"]];
    NSMutableArray* tmpUrls = [NSMutableArray array];
    for (int i = mUrlArray.count-1; i>=0; i--) {
        NSString* url = mUrlArray[i];
        // 過濾空的和jpg的圖像
        if (![url isEmptyOrWhitespace]) {
            // 在這裏處理圖片的URL
        }
    }
    NSLog(@"mUrlArray = %@   tmpUrls = %@", mUrlArray, tmpUrls);
    return tmpUrls;
}

參考資料：
App Extension Programming Guide