pinning-api/

Go API Server for tfpin

About this spec

The IPFS Pinning Service API is intended to be an implementation-agnostic API:

• For use and implementation by pinning service providers
• For use in client mode by IPFS nodes and GUI-based applications

Document scope and intended audience

The intended audience of this document is IPFS developers building pinning service clients or servers compatible with this OpenAPI spec. Your input and feedback are welcome and valuable as we develop this API spec. Please join the design discussion at github.com/ipfs/pinning-services-api-spec.

IPFS users should see the tutorial at docs.ipfs.io/how-to/work-with-pinning-services instead.

Related resources

The latest version of this spec and additional resources can be found at:

• Specification: https://github.com/ipfs/pinning-services-api-spec/raw/main/ipfs-pinning-service.yaml
• Docs: https://ipfs.github.io/pinning-services-api-spec/
• Clients and services: https://github.com/ipfs/pinning-services-api-spec#adoption

Schemas

This section describes the most important object types and conventions.

A full list of fields and schemas can be found in the schemas section of the YAML file.

Identifiers

cid

Content Identifier (CID) points at the root of a DAG that is pinned recursively.

requestid

Unique identifier of a pin request.

When a pin is created, the service responds with unique requestid that can be later used for pin removal. When the same cid is pinned again, a different requestid is returned to differentiate between those pin requests.

Service implementation should use UUID, hash(accessToken,Pin,PinStatus.created), or any other opaque identifier that provides equally strong protection against race conditions.

Objects

Pin object

The Pin object is a representation of a pin request.

It includes the cid of data to be pinned, as well as optional metadata in name, origins, and meta. Addresses provided in origins list are relevant only during the initial pinning, and don't need to be persisted by the pinning service.

Pin status response

The PinStatus object is a representation of the current state of a pinning operation. It includes values from the original Pin object, along with the current status and globally unique requestid of the entire pinning request, which can be used for future status checks and management. Addresses in the delegates array are peers designated by pinning service that will receive the pin data over bitswap (more details in the Provider hints section). Any additional vendor-specific information is returned in optional info.

The pin lifecycle

Creating a new pin object

The user sends a Pin object to POST /pins and receives a PinStatus response:

• requestid in PinStatus is the identifier of the pin operation, which can can be used for checking status, and removing the pin in the future
• status in PinStatus indicates the current state of a pin

Checking status of in-progress pinning

status (in PinStatus) may indicate one of the two pending states: queued or pinning:

• queued is passive: the pin was added to the queue but the service isn't consuming any resources to retrieve it yet. - pinning is active: the pinning service is trying to retrieve the CIDs by finding providers for all involved CIDs, connect to these providers and download data from them. When a new pin object is created it typically starts in a queued state. Once the pinning service actively seeks to retrieve the file it changes to pinning. pinning typically means that the data behind Pin.cid was not found on the pinning service and is being fetched from the IPFS network at large, which may take time. In either case, the user can periodically check pinning progress via GET /pins/{requestid} until pinning is successful, or the user decides to remove the pending pin.

Replacing an existing pin object

The user can replace an existing pin object via POST /pins/{requestid}. This is a shortcut for removing a pin object identified by requestid and creating a new one in a single API call that protects against undesired garbage collection of blocks common to both pins. Useful when updating a pin representing a huge dataset where most of blocks did not change. The new pin object requestid is returned in the PinStatus response. The old pin object is deleted automatically.

Removing a pin object

A pin object can be removed via DELETE /pins/{requestid}.

Provider hints

Provider hints take the form of two multiaddr lists: Pin.origins and PinStatus.delegates

Pin.origins

A list of known sources (providers) of the data. Sent by a client in a pin request. Pinning service will try to connect to them to speed up data transfer.

PinStatus.delegates

A list of temporary destination (retrievers) for the data. Returned by pinning service in a response for a pin request. These peers are provided by a pinning service for the purpose of fetching data about to be pinned.

Optimizing for speed and connectivity

Both ends should attempt to preconnect to each other:

• Delegates should always preconnect to origins
• Clients who initiate pin request and also have the pinned data in their own local datastore should preconnect to delegates

NOTE: Connections to multiaddrs in origins and delegates arrays should be attempted in best-effort fashion, and dial failure should not fail the pinning operation. When unable to act on explicit provider hints, DHT and other discovery methods should be used as a fallback by a pinning service.

Rationale

A pinning service will use the DHT and other discovery methods to locate pinned content; however, it may not be able to retrieve data if the only provider has no publicly diallable address (e.g. a desktop peer behind a restrictive NAT/firewall).

Leveraging provider hints mitigates potential connectivity issues and speeds up the content routing phase. If a client has the data in their own datastore or already knows of other providers, the transfer will start immediately.

The most common scenario is a client putting its own IPFS node's multiaddrs in Pin.origins, and then attempt to connect to every multiaddr returned by a pinning service in PinStatus.delegates to initiate transfer. At the same time, a pinning service will try to connect to multiaddrs provided by the client in Pin.origins.

This ensures data transfer starts immediately (without waiting for provider discovery over DHT), and mutual direct dial between a client and a service works around peer routing issues in restrictive network topologies, such as NATs, firewalls, etc.

NOTE: All multiaddrs MUST end with /p2p/{peerID} and SHOULD be fully resolved and confirmed to be dialable from the public internet. Avoid sending addresses from local networks.

Custom metadata

Pinning services are encouraged to add support for additional features by leveraging the optional Pin.meta and PinStatus.info fields. While these attributes can be application- or vendor-specific, we encourage the community at large to leverage these attributes as a sandbox to come up with conventions that could become part of future revisions of this API.

Pin metadata

String keys and values passed in Pin.meta are persisted with the pin object. This is an opt-in feature: It is OK for a client to omit or ignore these optional attributes, and doing so should not impact the basic pinning functionality.

Potential uses:

• Pin.meta[app_id]: Attaching a unique identifier to pins created by an app enables meta-filtering pins per app
• Pin.meta[vendor_policy]: Vendor-specific policy (for example: which region to use, how many copies to keep)

Filtering based on metadata

The contents of Pin.meta can be used as an advanced search filter for situations where searching by name and cid is not enough.

Metadata key matching rule is AND:

• lookup returns pins that have meta with all key-value pairs matching the passed values
• pin metadata may have more keys, but only ones passed in the query are used for filtering

The wire format for the meta when used as a query parameter is a URL-escaped stringified JSON object. A lookup example for pins that have a meta key-value pair {\"app_id\":\"UUID\"} is:

• GET /pins?meta=%7B%22app_id%22%3A%22UUID%22%7D

Pin status info

Additional PinStatus.info can be returned by pinning service.

Potential uses:

• PinStatus.info[status_details]: more info about the current status (queue position, percentage of transferred data, summary of where data is stored, etc); when PinStatus.status=failed, it could provide a reason why a pin operation failed (e.g. lack of funds, DAG too big, etc.)
• PinStatus.info[dag_size]: the size of pinned data, along with DAG overhead
• PinStatus.info[raw_size]: the size of data without DAG overhead (eg. unixfs)
• PinStatus.info[pinned_until]: if vendor supports time-bound pins, this could indicate when the pin will expire

Pagination and filtering

Pin objects can be listed by executing GET /pins with optional parameters:

• When no filters are provided, the endpoint will return a small batch of the 10 most recently created items, from the latest to the oldest.
• The number of returned items can be adjusted with the limit parameter (implicit default is 10).
• If the value in PinResults.count is bigger than the length of PinResults.results, the client can infer there are more results that can be queried.
• To read more items, pass the before filter with the timestamp from PinStatus.created found in the oldest item in the current batch of results. Repeat to read all results.
• Returned results can be fine-tuned by applying optional after, cid, name, status, or meta filters.

Note: pagination by the created timestamp requires each value to be globally unique. Any future considerations to add support for bulk creation must account for this.