Question

我有以下JS函数，它是mozilla thunderbird扩展的第一个原型。目标是连接到服务器并下载示例文件，然后解压缩并将内容存储在thunderbird配置文件文件夹中。现在一切正常，除了在文件系统上创建zip文件后停止执行该函数。所以我必须重新启动该函数，以便获取执行的函数的第二部分，从zip文件中提取user.js文件。任何想法可能是什么问题？

function downloadFile(httpLoc) {
    // get profile directory
    var file = Components.classes["@mozilla.org/file/directory_service;1"].
        getService(Components.interfaces.nsIProperties).
        get("ProfD", Components.interfaces.nsIFile);

    var profilePath = file.path;

    // change profile directory to native style
    profilePath = profilePath.replace(/\\/gi , "\\\\");
    profilePath = profilePath.toLowerCase();

    // download the zip file
    try {
        //new obj_URI object
        var obj_URI = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService).newURI(httpLoc, null, null);

        //new file object
        var obj_TargetFile = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile);

        //set to download the zip file into the profil direct
        obj_TargetFile.initWithPath(profilePath + "\/" + "test.zip");

        //if file the zip file doesn't exist, create it
        if(!obj_TargetFile.exists()) {

            alert("zip file wird erstellt");

            obj_TargetFile.create(0x00,0644);

        }

        //new persitence object
        var obj_Persist = Components.classes["@mozilla.org/embedding/browser/nsWebBrowserPersist;1"].createInstance(Components.interfaces.nsIWebBrowserPersist);


        // with persist flags if desired ??
        const nsIWBP = Components.interfaces.nsIWebBrowserPersist;
        const flags = nsIWBP.PERSIST_FLAGS_REPLACE_EXISTING_FILES;
        obj_Persist.persistFlags = flags | nsIWBP.PERSIST_FLAGS_FROM_CACHE;

        //save file to target
        obj_Persist.saveURI(obj_URI,null,null,null,null,obj_TargetFile);
    } catch (e) {
        alert(e);
    } finally {
        // unzip the user.js file to the profile direc

        // creat a zipReader, open the zip file
        var zipReader = Components.classes["@mozilla.org/libjar/zip-reader;1"]
            .createInstance(Components.interfaces.nsIZipReader);

        zipReader.open(obj_TargetFile); 

        //new file object, thats where the user.js will be extracted
        var obj_UnzipTarget = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile);

        //set path for the user.js
        obj_UnzipTarget.initWithPath(profilePath + "\/" + "user.js");

        // if user.js doesn't exist, create it
        if(!obj_UnzipTarget.exists()) {
            alert("user.js wird erstellt");

            obj_UnzipTarget.create(0x00,0644);
        }

        // extract the user.js out of the zip file, to the specified path
        zipReader.extract("user.js", obj_UnzipTarget);  

        zipReader.close();
    }
}

var hello = {
    click: function() {
        downloadFile("http://pse2.iam.unibe.ch/profiles/profile.zip");
    },
};

Answer 1

saveURI是异步的，因此您需要在persist对象上设置progress listener以了解它何时完成。以下是setting a progress listener的示例，稍后会有check to see whether the transfer has finished。

为什么这个JavaScript函数会停止执行？

1 个答案: