I want to perform some actions on X value depending on input from received in Y value. Can I perform such actions writing server side code in parse server?
Any pointers will be helpful.
Thanks.
Custom server side code can be achieved via cloud code. Cloud code allows you to create custom functions that are written in NodeJS and those functions can do various operations like: query from database, integrate with other solutions like: social, sending emails and more. The big advantage in parse-server is that you can use any npm module that you like from within the cloud code function and because there are millions of modules out there you have unlimited options.
Another very cool features of cloud code is the server side hooks
server side hooks allows you to write a code that will be triggered by parse-server core when an object is being saved or deleted. such events can be:
beforeSave - do something before the object is being saved to the database
afterSave - do something after the object is being saved
beforeDelete - do something before deleting
and more and more..
in order to define new cloud code function you will need to use the following code:
Parse.Cloud.define("{YOUR_FUNCTION_NAME}", function (request, response) {
// write your code, require some npm module and more...
});
In order to create server side hook you can write the following code:
Parse.Cloud.beforeSave("{PARSE_OBJECT_NAME}", function (request, response) {
// write your code and handle before saving an object
});
Triggering cloud code functions can be done easily via parse-server REST API or via parse-server client SDK's (iOS,Android,JavaScript and more)
There is a great guide on cloud code in here:
http://parseplatform.github.io/docs/cloudcode/guide/
Good Luck :)
Related
I'm using express-graqphl and was wondering if there is any concept of running a function before each graphql endpoint is executed? I'd like to have this for things like validating JWTs and other things. I realize we could use express for this, e.g.
app.use('/graphql`, doChecks);
but I'd like for the graphql handler to throw an error so it'll be inside the errors: [] list in the results giving the client a consistent experience with the api. Is there any direct support for this in the package?
The context function is executed before every request. If you're using Apollo v4+ then here are the docs
The context function is most often used to manage auth, including reading and validation of security tokens.
Background:
I'm building an SPA (Single Page Application) PWA (Progressive Web App) using Vue.js. I've a remote PostgreSQL database, serving the tables over HTTP with PostgREST. I've a working Workbox Service Worker and IndexedDB, which hold a local copy of the database tables. I've also registered some routes in my service-worker.js; everything is fine this far....
I'm letting Workbox cache GET calls that return tables from the REST service. For example:
https://www.example.com/api/customers will return a json object of the customers.
workbox.routing.registerRoute('https://www.example.com/api/customers', workbox.strategies.staleWhileRevalidate())
At this point, I need Workbox to do the stale-while-revalidate pattern, but to:
Not use a cache, but instead return the local version of this table, which I have stored in IndexedDB. (the cache part)
Make the REST call, and update the local version, if it has changed. (the network part)
I'm almost certain that there is no configurable option for this in this workbox strategy. So I would write the code for this, which should be fairly simple. The retrieval of the cache is simply to return the contents of the requested table from IndexedDB. For the update part, I'm thinking to add a data revision number to compare against. And thus decide if I need to update the local database.
Anyway, we're now zooming in on the actual question:
Question:
Is this actually a good way to use Workbox Routes/Caching, or am I now misusing the technology because I use IndexedDB as the cache?
and
How can I make my own version of the StaleWhileRevalidate strategy? I would be happy to understand how to simply make a copy of the existing Workbox version and be able to import it and use it in my Vue.js Service Worker. From there I can make my own necessary code changes.
To make this question a bit easier to answer, these are the underlying subquestions:
First of all, the StaleWhileRevalidate.ts (see link below) is a .ts (TypeScript?) file. Can (should) I simply import this as a module? I propably can. but then I get errors:
When I to import my custom CustomStaleWhileRevalidate.ts in my main.js, I get errors on all of the current import statements because (of course) the workbox-core/_private/ directory doesn't exist.
How to approach this?
This is the current implementation on Github:
https://github.com/GoogleChrome/workbox/blob/master/packages/workbox-strategies/src/StaleWhileRevalidate.ts
I don't think using the built-in StaleWhileRevalidate strategy is the right approach here. It might be possible to do what you're describing using StaleWhileRevalidate along with a number of custom plugin callbacks to override the default behavior... but honestly, you'd end up changing so much via plugins that starting from scratch would make more sense.
What I'd recommend that you do instead is to write a custom handlerCallback function that implements exactly the logic you want, and returns a Response.
// Your full logic goes here.
async function myCustomHandler({event, request}) {
event.waitUntil((() => {
const idbStuff = ...;
const networkResponse = await fetch(...);
// Some IDB operation go here.
return finalResponse;
})());
}
workbox.routing.registerRoute(
'https://www.example.com/api/customers',
myCustomHandler
);
You could do this without Workbox as well, but if you're using Workbox to handle some of your unrelated caching needs, it's probably easiest to also register this logic via a Workbox route.
I'm currently using a self hosted Parse Server up to date but I'm facing some security issues.
At the moment, calls done to the route /classes can retrieve any object in any table and, even though I might want an object to be public readable, I wouldn't like to show all the parameters of that object. Briefly I don't want the database to be retrieved in any case, I would like to disable "everything" except the Parse Cloud code. So that is, I would be able to run calls to my own functions, but not able to use clients (Android, iOS, C#, Javascript...) to retrieve data.
Is there any way to do this? I've been searching deeply for this, trying to debug some Controllers but I don't have any clue.
Thank you very much in advance.
tl;dr: set the ACL for all objects to be only readable when using the master key and then tell the query in Cloud Code to use the MK when querying your data
So without changing Parse Server itself you could make use of ACL and only allow a specific user to access objects. You would then "login" as that user in your Cloud Code and be able to access all objects.
As the old method, Parse.Cloud.useMasterKey() isn't available in the OS Parse Server you will have to pass the parameter useMasterKey to the query you are running which should do the trick for this particular request and will bypass ACL/CLP. There is an example in the Wiki of Parse Server as well.
For convenience, here is a short code example from the Wiki:
Parse.Cloud.define('getTotalMessageCount', function(request, response) {
var query = new Parse.Query('Messages');
query.count({
useMasterKey: true
}) // count() will use the master key to bypass ACLs
.then(function(count) {
response.success(count);
});
});
I want to use breezejs api for storing data in local storage (indexdb or websql) and also want to sync local data with sql server.
But I am failed to achieve this and also not able to find sample app of this type of application using breezejs, knockout and mvc api.
My requirement is:
1) If internet is available, the data will come from sql server by using mvc web api.
2) If internet is shutdown, the application will retrieve data from cached local storage (indexdb or websql).
3) As soon as internet is on, the local data will sync to sql server.
Please let me know Can I achieve this requirement by using breezejs api or not?
If yes, please provide me some and links and sample.
If no, what other can we use for achieving this type of requirement?
Thanks.
Please help me to meet this requirement.
You can do this, but I would suggest simply using localstorage. Basically, every time you read from the server or save to the server, you export the entities and save that to local storage. THen, when you need to read in the data, if the server is unreachable, you read the data from localstorage and use importentities to get it into the manager and then query locally.
function getData() {
var query = breeze.EntityQuery
.from("{YourAPI}");
manager.executeQuery.then(saveLocallyAndReturnPromise)
.fail(tryLocalRestoreAndReturnPromise)
// If query was successful remotely, then save the data in case connection
// is lost
function saveLocallyAndReturnPromise(data) {
// Should add error handling here. This code
// assumes tis local processing will be successful.
var cacheData = manager.exportEntities()
window.localStorage.setItem('savedCache',cacheData);
// return queried data as a promise so that this detour is
// transparent to viewmodel
return Q(data);
}
function tryLocalRestoreAndReturnPromise(error) {
// Assume any error just means the server is inaccessible.
// Simplified for example, but more robust error handling is
// warranted
var cacheData = window.localStorage.getItem('savedCache');
// NOTE: should handle empty saved cache here by throwing error;
manager.importEntities(cacheData); // restore saved cache
var query = query.using(breeze.FetchStrategy.FromLocalCache);
return manager.executeQuery(query); // this is a promise
}
}
This is a code skeleton for simplicity. You should check catch and handle errors, add an isConnected function to determine connectivity, etc.
If you are doing editing locally, there are a few more hoops to jump through. Every time you make a change to the cache, you will need to export either the whole cache or the changes (probably depending on the size of the cache). When there is a connection, you will need to test for local changes first and, if found, save them to the server before requerying the server. In addition, any schema changes made while offline complicate matters tremendously, so be aware of that.
Hope this helps. A robust implementation is a bit more complex, but this should give you a starting point.
I am a PHP dev looking to port my API over to the Parse platform.
Am I right in thinking that you only need cloud code for complex operations? For example, consider the following methods:
// Simple function to fetch a user by id
function getUser($userid) {
return (SELECT * FROM users WHERE userid=$userid LIMIT 1)
}
// another simple function, fetches all of a user's allergies (by their user id)
function getAllergies($userid) {
return (SELECT * FROM allergies WHERE userid=$userid)
}
// Creates a script (story?) about the user using their user id
// Uses their name and allergies to create the story
function getScript($userid) {
$user = getUser($userid)
$allergies = getAllergies($userid).
return "My name is {$user->getName()}. I am allergic to {$allergies}"
}
Would I need to implement getUser()/getAllergies() endpoints in Cloud Code? Or can I simply use Parse.Query("User")... thus leaving me with only the getScript() endpoint to implement in cloud code?
Cloud code is for computation heavy operations that should not be performed on the client, i.e. handling a large dataset.
It is also for performing beforeSave/afterSave and similar hooks.
In your example, providing you have set up a reasonable data model, none of the operations require cloud code.
Your approach sounds reasonable. I tend to put simply queries that will most likely not change on the client side, but it all depends on your scenario. When developing mobile apps I tend to put a lot of code in cloud code. I've found that it speeds up my development cycle. For example, if someone finds a bug and it's in cloud code, make the fix, run parse deploy, done! The change is available to all mobile environments instantly!!! If that same code is in my mobile app, it really sucks, cause now I have to fix the bug, rebuild, push it to the app store/google play, wait x number of days for it to be approved, have the users download it... you see where I'm going here.
Take for example your
SELECT * FROM allergies WHERE userid=$userid query.
Even though this is a simple query, what if you want to sort it? maybe add some additional filtering?
These are the kinds of things I think of when deciding where to put the code. Hope this helps!
As a side note, I have also found cloud code very handy when needing to add extra security to my apps.