docs/developers/provider/general-endpoints.md

General Endpoints

Nonce

Retrieves the last-used nonce value for a specific user's Ethereum address.

• Endpoint: GET /api/services/nonce
• Parameters: userAddress: This is a string that should contain the Ethereum address of the user. It is passed as a query parameter in the URL.
• Purpose: This endpoint is used to fetch the last-used nonce value for a user's Ethereum address. A nonce is a number that can only be used once, and it's typically used in cryptography to prevent replay attacks. While this endpoint provides the last-used nonce, it's recommended to use the current UTC timestamp as a nonce, where required in other endpoints.

Here are some typical responses you might receive from the API:

• 200: This is a successful HTTP response code. It means the server has successfully processed the request and returns a JSON object containing the nonce value.

Example response:

{
  "nonce": 23
}

Javascript Example

const axios = require('axios')

const response = await axios( `https://v4.provider.oceanprotocol.com/api/services/nonce?userAddress=0x0db823218e337a6817e6d7740eb17635deadafaf`)
 
console.log(response.status)
console.log(response.data)

File Info

Retrieves Content-Type and Content-Length from the given URL or asset.

• Endpoint: POST /api/services/fileinfo
• Parameters: The body of the request should contain a JSON object with the following properties:
  • did: This is a string representing the Decentralized Identifier (DID) of the dataset.
  • serviceId: This is a string representing the ID of the service.
• Purpose: This endpoint is used to retrieve the Content-Type and Content-Length from a given URL or asset. For published assets, did and serviceId should be provided. It also accepts file objects (as described in the Ocean Protocol documentation) and can compute a checksum if the file size is less than MAX_CHECKSUM_LENGTH. For larger files, the checksum will not be computed.
• Responses:
  • 200: This is a successful HTTP response code. It returns a JSON object containing the file info.

Example response:

[
    {
        "contentLength":"1161",
        "contentType":"application/json",
        "index":0,
        "valid": true
    },...
]

Javascript Example

Download

• Endpoint: GET /api/services/download
• Parameters: The query parameters for this endpoint should contain the following properties:
  • documentId: A string containing the document id (e.g., a DID).
  • serviceId: A string representing the list of file objects that describe each file in the dataset.
  • transferTxId: A hex string representing the ID of the on-chain transaction for approval of data tokens transfer given to the provider's account.
  • fileIndex: An integer representing the index of the file from the files list in the dataset.
  • nonce: The nonce.
  • consumerAddress: A string containing the consumer's Ethereum address.
  • signature: A string containing the user's signature (signed message).
• Purpose: This endpoint is used to retrieve the attached asset files. It returns a file stream of the requested file.
• Responses:
  • 200: This is a successful HTTP response code. It means the server has successfully processed the request and returned the file stream.