error handling

Six classes in src/exceptions.js. __hit decides which one to throw. The authenticated wrapper throws NotLoggedIn.

Hierarchy#

classDiagram
  class Error
  class APIError {
    name APIError
  }
  class LoginError {
    name LoginError
  }
  class SessionError {
    name SessionError
  }
  class SessionExpired {
    name SessionExpired
  }
  class NotLoggedIn {
    name NotLoggedIn
  }
  class AccountAPIError {
    name AccountAPIError
  }
  Error <|-- APIError
  APIError <|-- LoginError
  Error <|-- SessionError
  SessionError <|-- SessionExpired
  SessionError <|-- NotLoggedIn
  Error <|-- AccountAPIError

AccountAPIError does not extend APIError. instanceof APIError will not catch password failures.

Class	Base	Thrown from
`APIError`	`Error`	default `__hit`, `download_marks` catch
`LoginError`	`APIError`	`student_login`
`SessionError`	`Error`	not thrown directly
`SessionExpired`	`SessionError`	HTTP 401 in `__hit`
`NotLoggedIn`	`SessionError`	`authenticated()` when `session == null`
`AccountAPIError`	`Error`	`change_password`

Each constructor sets this.name to the class name.

`__hit` decisions#

flowchart TD
  f[fetch] --> t{throw?}
  t -->|HTTP 513| e513[exception: portal unavailable]
  t -->|HTTP 401| e401[SessionExpired]
  t -->|JSON status not Success| estat[exception with status JSON]
  t -->|TypeError message includes CORS| eCORS[exception: unavailable]
  t -->|other catch| eother[exception with error.message]

Condition	Class	Message
status 513	`options.exception` or `APIError`	`JIIT Web Portal server is temporarily unavailable (HTTP 513). Please try again later.`
status 401	always `SessionExpired`	`response.error` (Response has no `.error`; this is often `undefined`)
`resp.status.responseStatus !== "Success"`	`options.exception`	stringified `resp.status`
`TypeError` whose message includes `"CORS"`	`options.exception`	unavailable text without 513
other catch	`options.exception`	`error.message` or `"Unknown error"`

A successful HTTP 200 with a failure payload still throws.

flowchart LR
  login[student_login] --> LE[LoginError]
  pwd[change_password] --> AE[AccountAPIError]
  rest[other __hit callers] --> API[APIError]

Catching#

javascript

import { WebPortal, LoginError, NotLoggedIn, SessionExpired, APIError, AccountAPIError } from "jsjiit";

const portal = new WebPortal();
try {
  await portal.student_login(user, pass);
  await portal.get_attendance_meta();
} catch (e) {
  if (e instanceof LoginError) {
    // bad credentials or token endpoints
  } else if (e instanceof NotLoggedIn) {
    // forgot login
  } else if (e instanceof SessionExpired) {
    await portal.student_login(user, pass);
  } else if (e instanceof AccountAPIError) {
    // password change
  } else if (e instanceof APIError) {
    // 513, CORS, non-Success status
  } else {
    throw e;
  }
}

get_hostel_details can throw a plain Error. fill_feedback_form swallows per-row failures with continue.

flowchart TD
  call[authenticated method] --> sess{session null?}
  sess -->|yes| nl[NotLoggedIn]
  sess -->|no| hit[__hit]
  hit --> net[network / status]

There is no retry helper and no automatic re-login.

flowchart LR
  hostel[get_hostel_details missing response] --> native[Error Hostel details not found]
  fb[fill_feedback_form row fail] --> skip[continue]
  marks[download_marks fetch fail] --> api[APIError]

Jsjiit

Hierarchy#

__hit decisions#

Catching#

`__hit` decisions#