Today we are going to see how to open a javascript file, using a filepicker, in javascript applications for Windows 8, and process the files individually one by one.

Steps

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1. First we download the zip.js library from here these are the files we are interested in.

   

   inflate.js(compress), deflate.js (unzip)

2. // Creamos el objeto picker, con las opciones deseadas
       var openPicker = new Windows.Storage.Pickers.FileOpenPicker();
       openPicker.viewMode = Windows.Storage.Pickers.PickerViewMode.list;
       openPicker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.documentsLibrary;
       //Establecemos los formatos que queremos capturar
       openPicker.fileTypeFilter.replaceAll([".zip", ".ZIP"]);
   
       // pickSingleFilesAsync si solo queremos uno
       openPicker.pickMultipleFilesAsync().then(function (file) {
           if(file.size >0){
               for (var i = 0; i < file.size; i++) {
                   //imaginemos que contiene ficheros de texto
                   file[i].openReadAsync().then(function (stream) {
                       if (myFile) {
                           //Creamos un blob del archivo zip
                           var blob = MSApp.createBlobFromRandomAccessStream(myFile.contentType, stream);
   
                           //Para blob
                           zip.createReader(new zip.BlobReader(blob), function (reader) {
                               // Obtenemos los ficheros
                               reader.getEntries(function (entries) {
                                   //Accedemos a cada fichero
                                   entries.forEach(function (item) {
                                       item.getData(new zip.TextWriter(), function (data) {
                                           //"data" contiene el texto del fichero
                                       });
   
                                   });
   
                               });
   
                           }, function (error) {
                               // Error callback
                           });
   
                       }
                   });
   
               }
           } else {
               //Se ha presionado cancelar
           }
       });

3. As we can see, in this simple way, we will be able to open zip files with zip.js and winJS.

Notes

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This is applicable to text files (inside the zip), with UTF-8 encoding, soon we will see how to work with other encodings such as ISO 5598-1, ISO 5598-15 etc.

Wise note:

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Substituting

 zip.createReader(new zip.BlobReader(blob), function (reader) {

by

zip.createReader(new zip.HttpRangeReader(url), function (reader) {

We will be able to access files hosted on a website.