Google Calendar API

[pettechservices]

Has anyone had any success of using Google Calendar API with A5 ?

I have no real idea where to start, so was hoping for some guidance if anyone has done so.

thanks,
chris

[Sparticuz]

Re: Google Calendar API

I have alot of experience with it. In fact, I've been writing a XBasic class for it. I would HIGHLY recommend a few links from Google. https://developers.google.com/google.../v3/reference/ as well as https://developers.google.com/accounts/docs/OAuth2

Start with the OAuth2 article if your app is going to need authentication. Ask any questions you want and I've more than likely dealt with it. I'm not quite ready to share my XBasic class in total (not quite 100% complete), but I will definitely share snippets to help you out.

As for me, My app uses a Five different google accounts (for 5 different regions) and has between 4-7 individual calendars per account. A person can set an appointment by clicking a box and typing in a little bit of information. At that point, it saves the event to the correct calendar. (which is then available for syncing on smartphones). My code takes care of auth tokens (which must be refreshed every 60 minutes of use using a refresh token). I wrote this app before Alpha fixed their JSON implementation, so I use a 'man in the middle' PHP script to help with the JSON, but I've been meaning to convert it pure xbasic. I also use a jQuery calendar call FullCalendar (http://arshaw.com/fullcalendar/) which, when combined with one of my scripts, can also display events from Google calendar on my site.

Ask away :)

[pettechservices]

Re: Google Calendar API

Thank you for the reply! That is exactly what I'm trying to accomplish.. use a jQuery Calendar and have it sync to Google so it can sync with smartphones.

I think I can figure out the JSON stuff, but I'm just really stuck on how to implement the security oAuth2. Can you start by providing code to handle that by chance? I know very little of JSON but have been spending a lot of time reading about it today.

[Sparticuz]

Re: Google Calendar API

OK, a quick how to on oauth2. (Reference: https://developers.google.com/accounts/docs/OAuth2 )

1. First off, you must register your application with Google APIs Console.
   So create a project and go to Services, turning on Google Calendar API v3 (Free up to 25,000 Requests per day)
   Under API Access you will need to create a new Client ID for web apps.
   This will give you information that you will need later on.
   Reference: https://code.google.com/apis/console/
   
2. Next, we need to create a login URL. Even though, I personally, am not going to allow anyone login access, I still need to get the code response.
   I just wrote a quick a5w page and hand coded the variables in it. See Forming the URL in the url below. Make sure response_type is 'code' and that approval_prompt is 'force'. It needs to be force in order to get a refresh token. Going to the link you generate will bring you to a google login, then will return you back to whatever your redirect_uri is. (Make sure you set it up in your api's console)
   
   This will give you the code variable which we use in step 3
   Reference: https://developers.google.com/accoun...Auth2WebServer
   
3. Now that we have the code variable, we need to exchange it for a refresh_token. (See Handling the Response in the ref url.) I do have some sample code for this one
   

   function getRefreshTokenFromCode as p (redirect_uri as c)
   		'e.redirect_uri	
   		dim url as c = "https://accounts.google.com/o/oauth2/token?"
   		dim parameters as c = ""
   		
   		*concat(parameters,"code=&")
   		*concat(parameters,"client_id=&")
   		*concat(parameters,"client_secret=" + urlencode("") + "&")
   		if variable_exists("redirect_uri")
   			*concat(parameters,"redirect_uri=" + urlencode("")+ "&")
   		else
   			getRefreshTokenFromCode = "Redirect URI Required."
   		end if
   		*concat(parameters,"grant_type=authorization_code")
   		
   		response = http_post(url,parameters)
   		
   		'Do Some error checking, then decode from json
   		if response.parsed_headers.status_code != 200
   			getRefreshTokenFromCode = "Error" + response.body
   			end
   		end if
   		
   		dim json as p
   		json = json_parse(response.body)
   		
   		getRefreshTokenFromCode = json
   	end function

   What you want back from this POST call is refresh_token. SAVE THIS VARIABLE SOMEWHERE!!! You will need it to 'cash it in' for an access token (every 60 minutes)
   Reference: https://developers.google.com/accoun...Auth2WebServer
4. OK, so you've got a refresh_token, now you need to use that to get an access_token. In order to do this, you can use something similar to this:
   

   'Need to get new access token from the refresh token
   			dim url as c = "https://accounts.google.com/o/oauth2/token?"
   			dim parameters as c = ""
   			*concat(parameters,"refresh_token="+getRefreshToken()+"&")
   			*concat(parameters,"client_id=&")
   			*concat(parameters,"client_secret=&")
   			*concat(parameters,"grant_type=refresh_token")
   			
   			dim response as p = http_post(url,parameters)
   			'Decode response
   			if response.parsed_headers.status_code != 200
   				getAccessToken = "Error" + response.body
   			end if
   			
   			dim json as p = json_parse(response.body)
   			setAccessToken(json)

   This bit of code will get the access_token from google. YOU NEED TO SAVE THIS!!! It is good for the value in expires_in. (3600 seconds in my experience, (60 min). This is also something that needs to be saved. What I do is use a function 'getAccessToken()' that first checks the current time vs the expires_in time. If it's still valid it returns the access token, otherwise it uses the refresh token to get a new access token as well as a new expires_in time. getRefreshToken() is just a function call to lookup the refresh_token from the sql table.
5. And we've now got a valid access token! We are now authenticated to the google api, and can make authenticated api calls.

[Sparticuz]

Re: Google Calendar API

Part Two
---
Now that we've got a valid access_token, we can make authenticated calls to the API.

1. This is where I am using php helper functions, but with the improved json_parse() in alpha, you won't need to. For this example, I'll do an events call to the API.
   THIS IS PHP NOT XBASIC!!!!!
   

   //URL For List Events
   //https://developers.google.com/google-apps/calendar/v3/reference/events/list
   
   $url = "https://www.googleapis.com/calendar/v3/calendars/".$calendarId."/events";
   $url .= "?singleEvents=true";
   $url .= "&timeMin=".urlencode(date(DATE_ATOM,$start));
   $url .= "&timeMax=".urlencode(date(DATE_ATOM,$end));
   $url .= "&userIp=".urlencode($ip);
   
   $ch = curl_init( $url );
   	
   //Ask curl to return something from the server
   curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
   	
   //Turn off SSL Verification
   //TODO FIX HTTPS BY INSTALLING CERT
   curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
   	
   //Set the Authorization
   if(isset($access_token)){
   	$header = array(
   		"Authorization: Bearer " . $access_token
   	);
   	curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
   }
   $response = curl_exec( $ch );
   	
   curl_close( $ch );
   
   $response = json_decode($response, true);

   This php code could be improved upon in xbasic. For starters, xbasic has a http_post function that could handle my curls in php. Basically, all I'm doing is adding a header with the access_token in it for authentication. Like I said, eventually, I'll bring this in to alpha, but it won't be until January at the earliest.
2. Now I've got a decoded json_array in the $response variable. This contains all the info I need in order to generate the events needed for display on my calendar :)
3. Refer to https://developers.google.com/google...ce/events/list for information on the list events call

[pettechservices]

Re: Google Calendar API

Wow thank you so much!!! I'll start getting into all this and let you know. Thank you again!!! You are totally awesome!!

[pettechservices]

Re: Google Calendar API

Sparticuz,

I've finally been trying to get this to work, and I just do not know where to begin still. At the moment, all I want to do is insert a new appointment into my google calendar from my alpha5 web app. I come from a desktop dev environment and have done really good working on my web app in A5, but I just don't know where to put what code.

the username/password for the calendar would be hard coded into the request... I understand the PHP side of it (which I did some PHP programming but again, not an expert).

In all the above, I was able to get step 1 done. lol For step 2, I realize that I have to create the a5w page, but I do not know when it is called, and how it correlates to anything else (except when google returns the authorization).

Any chance of creating a short DEMO app on how to accomplish putting an event on a calendar?

[Graeme Smith UK]

Re: Google Calendar API

Hi Spaticuz

I was reading about this with interest. Did you write the new XBasic class ? If so do you have any further advice? thanks and best regards, Graeme Smith

I have alot of experience with it. In fact, I've been writing a XBasic class for it. I would HIGHLY recommend a few links from Google. https://developers.google.com/google.../v3/reference/ as well as https://developers.google.com/accounts/docs/OAuth2

Start with the OAuth2 article if your app is going to need authentication. Ask any questions you want and I've more than likely dealt with it. I'm not quite ready to share my XBasic class in total (not quite 100% complete), but I will definitely share snippets to help you out.

As for me, My app uses a Five different google accounts (for 5 different regions) and has between 4-7 individual calendars per account. A person can set an appointment by clicking a box and typing in a little bit of information. At that point, it saves the event to the correct calendar. (which is then available for syncing on smartphones). My code takes care of auth tokens (which must be refreshed every 60 minutes of use using a refresh token). I wrote this app before Alpha fixed their JSON implementation, so I use a 'man in the middle' PHP script to help with the JSON, but I've been meaning to convert it pure xbasic. I also use a jQuery calendar call FullCalendar (http://arshaw.com/fullcalendar/) which, when combined with one of my scripts, can also display events from Google calendar on my site.

Ask away :)

[Sparticuz]

Re: Google Calendar API

That's a negative. I knew someone would ask eventually. Feel free to ask any questions and I'll try to answer. (I have not cancelled writing it, just postponing it...)