Problem: I have earlier a visualforce page as a default tab, so the uaer is redirected to that visualforace tab when he\she logins. The Visualforce page has a custom header and the default header is hidden(showheader = false). Now I am in lightning experience and I can't remove the headers in the Lightning experience. So I started using the Lightning stand alone app, but I want the user to redirect to that app whenever the user login.
Question Is there a way to open a Lightning app directly when the user login ?

Problem: I have earlier a visualforce page as a default tab, so the uaer is redirected to that visualforace tab when he\she logins. The Visualforce page has a custom header and the default header is hidden(showheader = false). Now I am in lightning experience and I can't remove the headers in the Lightning experience. So I started using the Lightning stand alone app, but I want the user to redirect to that app whenever the user login.
Question Is there a way to open a Lightning app directly when the user login ?

I wish to understand this validation example in lightning

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/data_service_example.htm

In this example I want to understand "validateContactForm" method specially below part
What is this "reduce" and "showHelpMessageIfInvalid" do, any other reference help to understand it?

// Show error messages if required fields are blank
        var allValid = component.find('contactField').reduce(function (validFields, inputCmp) {
            inputCmp.showHelpMessageIfInvalid();
            return validFields && inputCmp.get('v.validity').valid;
        }, true);

 

Hi,
I am developing a lightning component to upload file in contentVersion object. I am refering to this site : 
http://webcache.googleusercontent.com/search?q=cache:yDEYXecmDHMJ:peterknolle.com/file-upload-lightning-component/+&cd=1&hl=en&ct=clnk&gl=in

I was successful uploading files upto 3 MB without chunking but I am facing some issue in chunking the file to upload the large files.
Wherever i upload the file , it gives me following error :
System.StringException: Unrecognized base64 character: %
I am attaching code for helper class and apex controller.

Helper Class :

({
    MAX_FILE_SIZE: 4 500 000, /* 6 000 000 * 3/4 to account for base64 */
    CHUNK_SIZE: 950 000, /* Use a multiple of 4 */

    readFile: function(component, helper, file) {
        if (!file) return;
        var reader = new FileReader();
        self = this;
        reader.onload = function() {
            var dataURL = reader.result;
            component.set("v.pictureSrc", "https://s3-us-west-1.amazonaws.com/sfdc-demo/image-placeholder.png");
            self.upload(component, file, dataURL);
        };
        reader.readAsDataURL(file);
    },

    upload: function(component, file, dataURL) {
        console.log('uploading file ...');
         var fromPos = 0;
        var toPos = Math.min(dataURL.length, fromPos + this.CHUNK_SIZE);
        console.log('toPos  '+toPos);
        console.log(' fromPos '+fromPos);
        this.uploadChunk(component, file, dataURL, fromPos, toPos,'');

    },
        uploadChunk : function(component, file, dataURL, fromPos, toPos,contentDocumentId){
            console.log('uploading chunk ');
             var action = component.get("c.saveTheChunkChatterFile");
            var chunk = dataURL.substring(fromPos, toPos);
            console.log(chunk);
            action.setParams({
            parentId: component.get("v.recordId"),
            fileName: file.name,
            base64Data: encodeURIComponent(chunk), 
            contentType: file.type,
            contentDocumentId :contentDocumentId
            });
            var self = this;
             action.setCallback(this, function(a) {
            contentDocumentId = a.getReturnValue();
            console.log('return value '+contentDocumentId);
            fromPos = toPos;
            toPos = Math.min(dataURL.length, fromPos + self.CHUNK_SIZE);    
            if (fromPos < toPos) {
                self.uploadChunk(component, file, dataURL, fromPos, toPos, contentDocumentId);  
            }else{
                component.set("v.message", "File Uploaded");
            }
        });
               component.set("v.message", "Uploading...");

            $A.enqueueAction(action); 
       }
})

Apex Controller : 
 

@AuraEnabled
public static Id saveChatterFiles(Id parentId, String fileName, String base64Data, String contentType)  { 
    system.debug('Saving chatter files '+fileName + ' '+ contentType);
    ContentVersion testContentInsert =new ContentVersion(); 
     testContentInsert.Title =fileName; 
    testContentInsert.VersionData=EncodingUtil.base64Decode(base64Data);
    testContentInsert.PathOnClient='/' + fileName ;
     insert testContentInsert; 
    system.debug('testContentInsert.id '+ testContentInsert.id);
    testContentInsert = [select id, ContentDocumentId from ContentVersion WHERE Id =: testContentInsert.Id];
    ContentDocumentLink cl = new ContentDocumentLink();
    cl.ContentDocumentId = testContentInsert.ContentDocumentId;
    cl.LinkedEntityId = parentId; 
    cl.ShareType = 'V';
     cl.Visibility = 'AllUsers';
    insert cl;
    system.debug('testContentInsert.id');
    return testContentInsert.id;

}


@AuraEnabled                            
public static Id saveTheChunkChatterFile(id parentId,String fileName, String base64Data, String contentType, String contentDocumentId){
        system.debug('saving chatter file');
    if (contentDocumentId == '' || contentDocumentId==null ) {
        system.debug('null id');
        contentDocumentId = saveChatterFiles(parentId, fileName, base64Data, contentType);
    } else {
        system.debug('not null id');
        system.debug('id '+contentDocumentId);
        appendToFileChatter(contentDocumentId, base64Data);
    }

    return Id.valueOf(contentDocumentId);
}

@AuraEnabled
public static void appendToFileChatter(Id contentDocumentId, String base64Data) {
 base64Data = EncodingUtil.urlDecode(base64Data, 'UTF-8');
    system.debug('appending');
    ContentVersion a = [
        SELECT Id, VersionData,ContentDocumentId
        FROM ContentVersion
        WHERE Id = :contentDocumentId
    ];

    String existingBody = EncodingUtil.base64Encode(a.VersionData);
    a.VersionData = EncodingUtil.base64Decode(existingBody + base64Data); 

    update a;
}

Any kind of help or alternative to upload file in contentVersion using lightning component will be greatful.