api.txt

====================
GET /<id> -- Retrieve a paste
====================
You must send an "Accept: application/json" header to receive a JSON body instead of HTML.
Response body:
{
  "status": "success" (string, see Handling Errors below for error details),
  "data": raw paste content (string),
  "expires": UTC paste expiration date in "YYYY-mm-dd HH:ii:ss" form (string)
}

====================
GET /webhook_key -- Retrieve the public key to verify webhook signatures
====================
This should be performed once and saved off in config rather than queried each time.
Response body:
{
  "status": "success" (string)
  "public": raw ed25519 public key (string)
}

====================
POST /submit -- Add a new paste
====================
The request body must be a JSON document.
Request body:
{
  "c": Paste contents (string)
}

Response body:
{
  "status": "success" (string, see Handling Errors below for error details),
  "url": fully qualified url to view paste (string)
}

====================
Error Messages
====================
When an error occurs, the response takes on the following form:
{
  "status": "error",
  "error": Description of the error (string)
}

Additionally, the HTTP status code will be indicative of the type of error that occurred.

====================
Webhooks
====================
If a webhook is configured, the system will send a POST request to the webhook destination.
The request will be signed by a configurable key (see GET /webhook_key) so that it can properly validate
the signature. To avoid replay attacks, the webhook destination may wish to look at the "date" and "nonce"
parameters and do things with them.

Request headers:
Content-Type: application/json; charset=utf-8
X-Webhook-Signature: base64-encoded signature over SHA-256 hash of request body
X-Webhook-Version: 1.0.0

Request body:
{
  "type": "newpaste" (string),
  "url": fully qualified url of paste (string),
  "nonce": unique hex string (string),
  "date": UTC current time in "YYYY-mm-dd HH:ii:ss" format (string)
}

To validate the signature, take the request body as-is (before parsing the json), calculate its SHA-256 hash,
and then compare that hash to the decrypted hash from the X-Webhook-Signature request header (base64-decode then decrypt
using the known public key using ed25519). If any of the following is true, the endpoint should reject the webhook
and take no action:
1. Decrypted signature does not match calculated signature
2. Nonce has been repeated in the past 30 minutes
3. Date is older than a few minutes ago (to allow for clock skew)
4. Request is coming from an IP outside of the known IP range(s) of the sender

The endpoint should return HTTP 200 OK if the webhook is successful and a 4xx or 5xx error code otherwise.
An optional response body may be sent, but it is currently ignored
This software does not currently examine or do anything about the error or response body, but that may change
in the future.