SqlStreamStore.FSharp

A thin F# wrapper around SQLStreamStore,
and SqlStreamStore.Postgres.

What does it do?

• Provides a nice API to interact with SqlStreamStore from F#
• Wraps all functions that can throw in Async<Result<'a, exn>>

Usage

This quick usage guide presumes familiarity with SQLStreamStore. A more in-depth guide and documentation are coming soon :)

Creating a store

Use the Create module.

    open SqlStreamStore
    open SqlStreamStore.FSharp
    open System
    // A new in memory store
    let inMemStore : IStreamStore = Create.inMemoryStore()
    let config : PostgresConfig = 
        {
            host = Environment.GetEnvironmentVariable "HOST"
            port = Environment.GetEnvironmentVariable "PORT"
            username = Environment.GetEnvironmentVariable "USERNAME"
            password = Environment.GetEnvironmentVariable "PASSWORD"
            database = Environment.GetEnvironmentVariable "DATABASE"
        } 
    // A new PostgresStore with a custom schema (use None if you want the tables to be created in public)
    let postgresStore : PostgresStreamStore = Create.postgresStore config (Some "my-cool-schema")    
    // Cast to IStreamStore
    let store : IStreamStore = postgresStore :> IStreamStore       
    // Or create schema if this is the first run 
    store |> Create.schemaIfNotExists       // : Async<Result<IStreamStore,exn>>

Appending to a stream

Use the Connect module to connect to the stream you want to append to, and then use the Append module to append
messages or events.

    open ...
    type MyEvent = 
        | Hi
        | Greeting of Greeting
    and Greeting = {data: string}
    let eventToAppend : NewStreamEvent<MyEvent> = 
        Greeting {data = "hello there!"}
        |> NewStreamEvent.create "me"
    // Given an IStreamStore called store
    store                                               // IStreamStore
    |> Connect.toStream "my-cool-stream"                // Stream
    |> Append.streamEvents [eventToAppend]              // AsyncResult<AppendResult, exn>

Reading and getting some data from a stream

Use the Read module to read the stream and then the Get module to get some data without having to bind the result of
the read operation.

    open ...
    // Using the MyType declared before and an IStreamStore called store
    store                                               // IStreamStore
    |> Connect.toStream "my-cool-stream"                // Stream 
    |> Read.entire                                      // Async<Result<ReadStreamPage,exn>>
    |> Get.messagesData                                 // Async<Result<string,exn>>

What if I want to read the stream backwards and specify if I want to prefetch the data, and all the cool stuff that already exists in SQLStreamStore?

Well each of the above functions has an alternative version call that has a ' at the end for the function’s name. The
alternative function takes a list of options as a parameter.

Why do this?

Because 90% of the time these options aren’t used, and this is an elegant way to hide them without having to use
builder-pattern.

Example

    open ...
    // Using the MyType declared before and an IStreamStore called store
    store                                               // IStreamStore
    |> Connect.toStream "my-cool-stream"                // Stream 
    |> Read.entire' [
                     ReadEntireOption.FromVersionInclusive 50
                     ReadEntireOption.NoPrefetch
                     ReadEntireOption.ReadBackwards
                     ]                                  // Async<Result<ReadStreamPage,exn>>
    |> Get.messagesData                                 // Async<Result<string,exn>>