Context in ParseSwift save

lsmilek1 · May 8, 2021, 11:11am

Hello, is there a way how to pass date as context for the .save() function in ParseSwift SDK? Thanks!

cbaker6 · May 8, 2021, 2:25pm

If I’m understanding the comment on how context was added to the JS SDK correctly

Comment by mtrezza - add context to Parse.Object.save

parse-community:master ← mtrezza:add-context-to-save

The context is transmitted as `_context` property in REST request body as part o…f the object properties. I did not find an existing similar use of internal properties in the REST request, but according to the [docs](https://docs.parseplatform.org/js/guide/#data-storage) a field name must start with a letter, so there cannot be a conflict with an object property: > Key names must contain only numbers, letters, and underscore, and must start with a letter. So using `_context` as internal property in a REST request seems OK, it is also used for internal field names such as `_created_at` in the DB.

The context is added to the property of the ParseObject. If this is true, ParseSwift’s design allows you to do this easily by just defining the property in your struct:

struct GameScore: ParseObject {
   ...
   var _context: [String: String]? // Or any encodable object. I don’t use context, so not sure what it needs to look like. 
}

This will probably not be officially added to the Swift SDK as it will add some unnecessary complexity due to context being able to be any Encodable and I don’t see a reason to require users to add a _context property to all of their objects which will happen if it’s officially added to the SDK.

Try what I mentioned above and let me know if it works.

lsmilek1 · May 8, 2021, 2:51pm

it throws following error without trying to read the context in beforeSave trigger:

ParseError(code: ParseSwift.ParseError.Code.invalidKeyName, message: “Invalid field name for update: _context”)

Also in Manuel’s example, he is accessing the context in the request itself, not the request.object

Parse.Cloud.beforeSave("TestObject", req => {
    console.log(req.context.a);
});

the error sounds like I would need to add the field _context also as a field in the database

cbaker6 · May 8, 2021, 3:24pm

You can look in API to see where it should be added Parse-Swift/API.swift at main · parse-community/Parse-Swift · GitHub

I don’t use context, so I don’t know much about it.

cbaker6 · May 12, 2021, 12:26am

From what I understand, context currently can’t be used by the Swift SDK because it doesn’t seem to be fully implemented on the server-side:

github.com

parse-community/parse-server/blob/9ea355b4635226ae4da17c8cc5fb0321e3fdec5e/src/middlewares.js#L38


var info = {
  appId: req.get('X-Parse-Application-Id'),
  sessionToken: req.get('X-Parse-Session-Token'),
  masterKey: req.get('X-Parse-Master-Key'),
  installationId: req.get('X-Parse-Installation-Id'),
  clientKey: req.get('X-Parse-Client-Key'),
  javascriptKey: req.get('X-Parse-Javascript-Key'),
  dotNetKey: req.get('X-Parse-Windows-Key'),
  restAPIKey: req.get('X-Parse-REST-API-Key'),
  clientVersion: req.get('X-Parse-Client-Version'),
  context: {},
};


var basicAuth = httpAuth(req);


if (basicAuth) {
  var basicAuthAppId = basicAuth.appId;
  if (AppCache.get(basicAuthAppId)) {
    info.appId = basicAuthAppId;
    info.masterKey = basicAuth.masterKey || info.masterKey;
    info.javascriptKey = basicAuth.javascriptKey || info.javascriptKey;

It seems like it should of had a dedicated header added which is currently missing from above. Probably best for @Manuel to confirm if this is true since he made the discussion and PR to expose context and may know more about it’s origins and why it doesn’t have a header (PR).

The JS SDK adds a _context key to the body for it to work. The Swift SDK doesn’t ever add keys like this to the body (this looks a little hacky IMO, but from the comments it seems some of the other SDKs do it). If there’s a header added on the server side or perhaps a different way to use it that someone mentions then it will be an easy add to the Swift SDK. Until then, context won’t be added to the Swift SDK.

cbaker6 · May 12, 2021, 2:40pm

I’ve opened a PR on the Swift SDK to support context:

github.com/parse-community/Parse-Swift

Add context header. Improve query constraint comparison

parse-community:main ← parse-community:context

opened 02:15PM - 12 May 21 UTC

cbaker6

+522 -52

Adds context header option. This requires server level header support, `X-Parse-…Context` (currently missing here: https://github.com/parse-community/parse-server/blob/9ea355b4635226ae4da17c8cc5fb0321e3fdec5e/src/middlewares.js#L38). If added on the server level, will only work with parse-server > 4.5.0. - [x] Added context header option - [x] Improved query constraint comparisons - [x] Improved API header tests - [x] Added playground `context` example - [x] Improve LiveQuery section of readme - [x] Update Jazzy docs to 0.13.7 - [x] Added changelog - [x] Prepare for release

As I mentioned in the previous comment, the server would have to receive header support for X-Parse-Context for it to work.

cbaker6 · June 20, 2021, 3:12pm

A PR has been created on the parse-server to enable context in a way that will work with the Swift SDK.

github.com/parse-community/parse-server

Accept context via header X-Parse-Cloud-Context

parse-community:master ← cbaker6:context

opened 02:51PM - 20 Jun 21 UTC

cbaker6

+247 -3

### New Pull Request Checklist  - [x] I am not disclosing a [vulnerability](https://github.com/parse-community/parse-server/blob/master/SECURITY.md). - [x] I am creating this PR in reference to #7438. ### Issue Description Related issue: Currently `context` is setup to accept an object in the header, but no header is available. This allows client SDK's to add context via a header instead of injecting `_context` in the body of JSON object, forcing the parse-server to have to delete it in middleware. Close #7438 ### Approach Add a new header for content called `X-Parse-Cloud-Context`. ### TODOs before merging  - [x] Add test cases - [x] Add entry to changelog