How to manipulate Google Drive files

download.js

/*
Download a file
*/
function downloadFile(fileId) {
  var request = gapi.client.drive.files.get({
    'fileId': fileId
  });
  request.execute(function(resp) {
    window.location.assign(resp.webContentLink);
  });
}

drive.js

/*
Get contents
*/
function getContentOfFile(theID){ //gets the content of the file
    current = theID;
    gapi.client.request({'path': '/drive/v2/files/'+theID,'method': 'GET',callback: function ( theResponseJS, theResponseTXT ) {
    var myToken = gapi.auth.getToken();
		var myXHR   = new XMLHttpRequest();
        myXHR.open('GET', theResponseJS.downloadUrl, true );
        myXHR.setRequestHeader('Authorization', 'Bearer ' + myToken.access_token );
        myXHR.onreadystatechange = function( theProgressEvent ) {
            if (myXHR.readyState == 4) {
                if ( myXHR.status == 200 ) {
                	var code = myXHR.response;
		}
            }
        }
        myXHR.send();
        }
    });
}

insert.js

/*
Now to create a new file
*/
function insertNewFile(folderId) {
	var content = " ";
	var FolderId = "";
	var contentArray = new Array(content.length);
        for (var i = 0; i < contentArray.length; i++) {
            contentArray[i] = content.charCodeAt(i);
        }
        var byteArray = new Uint8Array(contentArray);
        var blob = new Blob([byteArray], {type: 'text/plain'}); 
	insertFile(blob, fileInserted, folderId);
}
function fileInserted(d) {
	setPercent("100");
  var FI = FolderId;
	if(FI !== myRootFolderId){	
		insertFileIntoFolder(FI, d.id);
		removeFileFromFolder(d.parents[0].id,d.id);
	}
	openFile(d.id);
}
function insertFileIntoFolder(folderId, fileId) {
  var body = {'id': folderId};
  var request = gapi.client.drive.parents.insert({
    'fileId': fileId,
    'resource': body
  });
  request.execute(function(resp) { });
}
function removeFileFromFolder(folderId, fileId) {
  var request = gapi.client.drive.parents.delete({
    'parentId': folderId,
    'fileId': fileId
  });
  request.execute(function(resp) { });
}
function insertFile(fileData, callback, folderId) {
	setPercent("90");
  const boundary = '-------314159265358979323846';
  const delimiter = "\r\n--" + boundary + "\r\n";
  const close_delim = "\r\n--" + boundary + "--";

  var reader = new FileReader();
  reader.readAsBinaryString(fileData);
  reader.onload = function(e) {
    var contentType = fileData.type || 'application/octet-stream';
    var metadata = {
      'title': "untitled.txt",
      'mimeType': contentType
    };

    var base64Data = btoa(reader.result);
    var multipartRequestBody =
        delimiter +
        'Content-Type: application/json\r\n\r\n' +
        JSON.stringify(metadata) +
        delimiter +
        'Content-Type: ' + contentType + '\r\n' +
        'Content-Transfer-Encoding: base64\r\n' +
        '\r\n' +
        base64Data +
        close_delim;

    var request = gapi.client.request({
        'path': '/upload/drive/v2/files',
        'method': 'POST',
        'params': {'uploadType': 'multipart'},
        'headers': {
          'Content-Type': 'multipart/mixed; boundary="' + boundary + '"'
        },
        'body': multipartRequestBody});
    if (!callback) {
      callback = function(file) {
      };
    }
    request.execute(callback);
  }
}

permissions.js

/*
Check the permissions of a file
*/
function getP(fileId) {
	var request = gapi.client.drive.permissions.list({
		'fileId': fileId
	});
	request.execute(function(resp) {
		console.log(resp.items);
		console.log(resp.items.length);
		var ret = false;
		for(i = 0; i < resp.items.length; i++){
			console.log(resp.items[i]);
			if(resp.items[i].id === userId || resp.items[i].id === "anyone" || resp.items[i].id === "anyoneWithLink"){
				ret = true;
			}
		}
		console.log(ret);
		if(ret === false){
			//you don't have permission
		}
		else{
		  //ok!
		}
	});
}

rename.js

/*
Rename a file
*/
function renameFile(fileId, newTitle) {
  var body = {'title': newTitle};
  var request = gapi.client.drive.files.patch({
    'fileId': fileId,
    'resource': body
  });
  request.execute(function(resp) {
    console.log('New Title: ' + resp.title);
  });
}

save.js

/*
How to update a file
*/
function saveFile(fileId, content){
    if(typeof content !== "undefined"){ 
        var contentArray = new Array(content.length);
        for (var i = 0; i < contentArray.length; i++) {
            contentArray[i] = content.charCodeAt(i);
        }
        var byteArray = new Uint8Array(contentArray);
        var blob = new Blob([byteArray], {type: 'text/plain'});
        var request = gapi.client.drive.files.get({'fileId': fileId});
        request.execute(function(resp) {
            updateFile(fileId,resp,blob,changesSaved);
        });
    }
}
function updateFile(fileId, fileMetadata, fileData, callback) { 
  if(ok){
  const boundary = '-------314159265358979323846';
  const delimiter = "\r\n--" + boundary + "\r\n";
  const close_delim = "\r\n--" + boundary + "--";

  var reader = new FileReader();
  reader.readAsBinaryString(fileData);
  reader.onload = function(e) {
    var contentType = fileData.type || 'application/octet-stream';
    var base64Data = btoa(reader.result);
    var multipartRequestBody =
        delimiter +
        'Content-Type: application/json\r\n\r\n' +
        JSON.stringify(fileMetadata) +
        delimiter +
        'Content-Type: ' + contentType + '\r\n' +
        'Content-Transfer-Encoding: base64\r\n' +
        '\r\n' +
        base64Data +
        close_delim;

    var request = gapi.client.request({
        'path': '/upload/drive/v2/files/' + fileId,
        'method': 'PUT',
        'params': {'uploadType': 'multipart', 'alt': 'json'},
        'headers': {
          'Content-Type': 'multipart/mixed; boundary="' + boundary + '"'
        },
        'body': multipartRequestBody});
    if (!callback) {
      callback = function(file) {
      };
    }
    request.execute(callback);
  }
	}
}

title.js

/*
Get the title of a file
*/
function getTitle(fileId){
	var request = gapi.client.drive.files.get({
    'fileId': fileId
  	});
  	request.execute(function(resp) {
  		title = resp.title;
		if(typeof title === 'undefined' || title === "undefined"){
			//error
			return false;
		}
  		document.getElementById('renameInput').value = title;
    		checkFileName(resp.title);
  	});
}

token.js

/*
How to refresh your access token (they expire every hour)
*/
window.setInterval(function(){
	refreshToken();
},3000000); //<--this is in milliseconds
function refreshToken() {
	gapi.auth.authorize({'client_id': CLIENT_ID, 'scope': SCOPES.join(' '), 'immediate':true},tokenRefreshed);
	//you have to get your client id and the proper scopes
	window.setInterval(function(){
		refreshToken();
	},3000000);
}
function tokenRefreshed(result){
}

user.js

/*
Get user info
*/
function user() {
	var request = gapi.client.drive.about.get();
	request.execute(function(resp) {
		try{
			var myRootFolderId = resp.rootFolderId;
			var userName = resp.name;		
			var userUrl = resp.user.picture.url;
			var userId = resp.user.permissionId;
			var total_q = resp.quotaBytesTotal;
			var user_q = resp.quotaBytesUsedAggregate;
		}
		catch(e){
			//error!
		}
	});
}

@SabbaKilam did you answered that question?