v0.5.2 (2018-10-07)

• Fixed: When using the Echo middleware the invoice response status code was 200 OK instead of 402 Payment Required (issue #30)
• Fixed: When using the Echo middleware error responses (including the invoice) were wrapped in JSON instead of just text (issue #30)
• Fixed: GoDoc for storage.NewBoltClient(...) contained usage suggestions that would lead to the possibility of clients cheating with reusing preimages

v0.5.1 (2018-10-02)

• Fixed: Performance decreased when using Lightning Charge and the amount of invoices in the Lightning Charge server increased (issue #28)
• Fixed: Since the introduction of the ln.Invoice struct the whole struct was logged instead of just the invoice string

Breaking changes

Note: The following breaking changes don't affect normal users of the package, but only those who use their own implementations of our interfaces.

• Changed: The struct ln.Invoice now has a field ImplDepID string which is required by the middlewares. It's an LN node implementation dependent ID (e.g. payment hash for lnd, some random string for Lightning Charge). (Required for issue #28.)
• Changed: wall.LNclient now requires the method CheckInvoice(string) (bool, error) to accept the LN node implementation dependent ID instead of the preimage hash as parameter. (Required for issue #28.)

v0.5.0 (2018-09-24)

• Added: Support for c-lightning with Lightning Charge (issue #6)
  • Note: The current implementation's performance decreases with the amount of invoices in the Lightning Charge server. This will be fixed in an upcoming release.
• Added: Package pay (issue #20)
  • Interface pay.LNclient - Abstraction of a Lightning Network node client for paying LN invoices. Enables developers to write their own implementations if the provided ones aren't enough.
  • Struct pay.Client - Replacement for a standard Go http.Client
    • Factory function NewClient(httpClient *http.Client, lnClient LNclient) Client - httpClient can be passed as nil, leading to http.DefaultClient being used
    • Method Do(req *http.Request) (*http.Response, error) - Meant to be used as equivalent to the same Go http.Client method, but handles the Lightning Network payment in the background.
    • Method Get(url string) (*http.Response, error) - A convenience method for the Do(...) method, also an equivalent to the same Go http.Client method (regarding its usage)
  • Example client in examples/client/main.go

  • Note: Currently only ln.LNDclient can be used in the client, because Lightning Charge doesn't support sending payments (and maybe never will)

• Added: Method Pay(invoice string) (string, error) for ln.LNDclient - Implements the new pay.LNclient interface, so that the LNDclient can be used as parameter in the pay.NewClient(...) function. (Issue #20)
• Fixed: A client could cheat in multiple ways, for example use a preimage for a request to endpoint A while the invoice was for endpoint B, with B being cheaper than A. Or if the LN node is used for other purposes as well, a client could send any preimage that might be for a totally different invoice, not related to the API at all. (Issue #16)
• Fixed: Some info logs were logged to stderr instead of stdout

Breaking changes

• Changed: The preimage in the X-Preimage header must now be hex encoded instead of Base64 encoded. The hex encoded representation is the typical representation, as used by "lncli listpayments", Eclair on Android and bolt11 payment request decoders like https://lndecode.com. Base64 was used previously because "lncli listinvoices" uses that encoding. (Issue #8)
• Changed: Interface wall.StorageClient and thus all its implementations in the storage package were significantly changed. The methods are now completely independent of any ln-paywall specifics, with Set(...) and Get(...) just setting and retrieving any arbitrary interface{} to/from the storage. (Required for issue #16.)
• Changed: The method GenerateInvoice(int64, string) (string, error) in the interface wall.LNclient was changed to return a ln.Invoice object, which makes it much easier to access the invoice ID (a.k.a. preimage hash, a.k.a. payment hash), instead of having to decode the invoice. (Useful for issue #16, in which the invoice ID is required as key in the storage.)

v0.4.0 (2018-09-03)

Warning: This release contains a lot of renamings and refactorings, so your code will most definitely break. But it paves the way to upcoming features and makes some things easier, like automated testing.

• Added: Package-level documentation
• Improved: In case of an invalid preimage the error response is much more detailed now. It differentiates between several reasons why the preimage is invalid. Additionally more cases of invalid requests are detected now, so a proper 400 Bad Request is returned instead of a 500 Internal Server Error. (Issue #11)
• Improved: Increased performance when creating multiple middleware instances, because the LN client implementation can now be passed into the middleware factory function and be reused across multiple middleware instances. Previously the LN client was created internally, and a new instance was created with every middleware instance.
  • Not measured, but probably a bit lower memory consumption and a bit less traffic. Probably not much regarding speed.
• Fixed: Wrong spelling in an error message

Breaking changes

• Changed: Renamed package from pay to wall - this enables us to create a package called pay for client-side payments to the paywall in the future
• Changed: Moved all storage implementations to the new package storage
• Changed: Moved LNDoptions and DefaultLNDoptions to the from the wall (former pay) package to the ln package
  • This leads to the same kind of separation and loose coupling as with the storages
• Changed: All middleware factory functions now take a LNclient as second parameter instead of LNDoptions
  • This also leads to the same kind of separation and loose coupling as with the storages
  • In addition it enables proper mocking of the LN client for tests (preparation for issue #10)
  • As well as own implementations of LN clients (preparation for issue #6)

v0.3.0 (2018-08-12)

• Added: pay.NewEchoMiddleware(...) - A middleware factory function for Echo (issue #2)
• Added: Bolt DB client (issue #3)
  • Struct pay.BoltClient - Implements the StorageClient interface
  • Factory function NewBoltClient(...)
  • Struct pay.BoltOptions - Options for the BoltClient
  • Var pay.DefaultBoltOptions - a BoltOptions object with default values
• Added: pay.LNclient - An abstraction of a client that connects to a Lightning Network node implementation (like lnd, c-lightning and eclair)
  • Implemented for issue #4, but will be useful for issue #6 as well
• Added: ln.LNDclient - Implements the pay.LNclient interface (issue #4)
  • Factory function ln.NewLNDclient(...)
• Improved: Increased middleware performance by reusing the gRPC connection to the lnd backend (issue #4)
  • With the same setup (local Gin web service, pay.GoMap as storage client, remote lnd, same hardware) it took about 100ms per request before, and takes about 25ms per request now. Measured from the arrival of the initial request until the sending of the response with the Lightning invoice (as logged by Gin).
• Fixed: Success log message mentioned "HandlerFunc" in all middlewares despite it not always being a HandlerFunc
• Fixed: A wrong HTTP status code was used in responses when an internal error occurred (400 Bad Request instead of 500 Internal Server Error)

Breaking changes

Package pay:

• Changed: Renamed pay.InvoiceOptions.Amount to pay.InvoiceOptions.Price to avoid misunderstandings

Package ln (none of these changes should affect anyone, because this package is meant to be used only internally):

• Removed: ln.NewLightningClient(...) - Not required anymore after adding the much more usable ln.NewLNDclient(...).
• Changed: ln.GenerateInvoice(...) from being a function to being a method of ln.LNDclient and removed all lnd connection-related parameters which are part of the LNDclient. (issue #4)
• Changed ln.CheckInvoice(...) from being a function to being a method of ln.LNDclient and removed all lnd connection-related parameters which are part of the LNDclient. (issue #4)

v0.2.0 (2018-07-29)

• Added: Interface pay.StorageClient - an abstraction for multiple storage clients, which allows you to write your own storage client for storing the preimages that have already been used as payment proof in a request (issue #1)
  • Methods WasUsed(string) (bool, error) and SetUsed(string) error
• Added: Struct pay.RedisClient - implements the StorageClient interface (issue #1)
  • Factory function NewRedisClient(...)
• Added: Var pay.DefaultRedisOptions - a RedisOptions object with default values
• Added: Struct pay.GoMap - implements the StorageClient interface (issue #1)
  • Factory function NewGoMap()
• Improved: Increased middleware performance and decreased load on the connected lnd when invalid requests with the x-preimage header are received (invalid because the preimage was already used) - Instead of first getting a corresponding invoice for a preimage from the lnd and then checking if the preimage was used already, the order of these operations was switched, because then, if the preimage was already used, no request to lnd needs to be made anymore.
• Improved: All fields of the struct pay.RedisOptions are now optional

Breaking changes

Package pay:

• Changed: pay.NewHandlerFuncMiddleware(...), pay.NewHandlerMiddleware(...) and pay.NewGinMiddleware(...) now take a ln.StorageClient instead of a *redis.Client as parameter (issue #1)

Package ln (none of these changes should affect anyone, because this package is meant to be used only internally):

• Changed: ln.CheckPreimage(...) was renamed to ln.CheckInvoice(...) and doesn't check the storage anymore. The ln methods are supposed to just handle lightning related things and nothing else.
• Removed: Package lnrpc - Instead of using our own generated lnd gRPC Go file, import the one from Lightning Labs.

v0.1.0 (2018-07-02)

Initial release after working on the project during the "Chainhack 3" Blockchain hackathon.

• Go middlewares for:
  • net/http HandlerFunc
  • net/http Handler
    • Compatible with routers like gorilla/mux and chi
  • Gin
• Supported Lightning Network node:
  • lnd
• Supported storage:
  • Redis