Read content of SP.File object as text using JSOM - sharepoint-2013

Question

as the title suggests, I am trying to read the contents of a simple text file using JSOM. I am using a Sharepoint-hosted addin for this, the file I am trying to read resides on the host web in a document library.
Here's my JS code:
function printAllListNamesFromHostWeb() {
context = new SP.ClientContext(appweburl);
factory = new SP.ProxyWebRequestExecutorFactory(appweburl);
context.set_webRequestExecutorFactory(factory);
appContextSite = new SP.AppContextSite(context, hostweburl);
this.web = appContextSite.get_web();
documentslist = this.web.get_lists().getByTitle('Documents');
var camlQuery = new SP.CamlQuery();
camlQuery.set_viewXml('<View><ViewFields><FieldRef Name="Name"/></ViewFields></View>');
listitems = documentslist.getItems(camlQuery);
context.load(listitems, 'Include(File,FileRef)');
context.executeQueryAsync(
Function.createDelegate(this, successHandler),
Function.createDelegate(this, errorHandler)
);
function successHandler() {
var enumerator = listitems.getEnumerator();
while (enumerator.moveNext()) {
var results = enumerator.get_current();
var file = results.get_file();
//Don't know how to get this to work...
var fr = new FileReader();
fr.readAsText(file.get);
}
}
function errorHandler(sender, args) {
console.log('Could not complete cross-domain call: ' + args.get_message());
}
}
However, in my succes callback function, I don't know how I can extract the contents of the SP.File object. I tried using the FileReader object from HTML5 API but I couldn't figure out how to convert the SP.File object to a blob.
Can anybody give me a push here?

Answer 1

Once file url is determined file content could be loaded from the server using a regular HTTP GET request (e.g. using jQuery.get() function)
Example
The example demonstrates how to retrieve the list of files in library and then download files content
loadItems("Documents",
function(items) {
var promises = $.map(items.get_data(),function(item){
return getFileContent(item.get_item('FileRef'));
});
$.when.apply($, promises)
.then(function(content) {
console.log("Done");
//print files content
$.each(arguments, function (idx, args) {
console.log(args[0])
});
},function(e) {
console.log("Failed");
});
},
function(sender,args){
console.log(args.get_message());
}
);
where
function loadItems(listTitle,success,error){
var ctx = SP.ClientContext.get_current();
var web = ctx.get_web();
var list = web.get_lists().getByTitle(listTitle);
var items = list.getItems(createAllFilesQuery());
ctx.load(items, 'Include(File,FileRef)');
ctx.executeQueryAsync(
function() {
success(items);
},
error);
}
function createAllFilesQuery(){
var qry = new SP.CamlQuery();
qry.set_viewXml('<View Scope="RecursiveAll"><Query><Where><Eq><FieldRef Name="FSObjType" /><Value Type="Integer">0</Value></Eq></Where></Query></View>');
return qry;
}
function getFileContent(fileUrl){
return $.ajax({
url: fileUrl,
type: "GET"
});
}