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Update README.md #208

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57 changes: 29 additions & 28 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

[comment]: # (Start Badges)

[![Join the chat at https://gitter.im/47deg/fetch](https://badges.gitter.im/47deg/fetch.svg)](https://gitter.im/47deg/fetch?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![Build Status](https://travis-ci.org/47deg/fetch.svg?branch=master)](https://travis-ci.org/47deg/fetch) [![codecov.io](http://codecov.io/gh/47deg/fetch/branch/master/graph/badge.svg)](http://codecov.io/gh/47deg/fetch) [![Maven Central](https://img.shields.io/badge/maven%20central-1.1.0-green.svg)](https://oss.sonatype.org/#nexus-search;gav~com.47deg~fetch*) [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](https://raw.githubusercontent.com/47deg/fetch/master/LICENSE) [![Latest version](https://img.shields.io/badge/fetch-1.1.0-green.svg)](https://index.scala-lang.org/47deg/fetch) [![Scala.js](http://scala-js.org/assets/badges/scalajs-0.6.17.svg)](http://scala-js.org) [![GitHub Issues](https://img.shields.io/github/issues/47deg/fetch.svg)](https://github.com/47deg/fetch/issues)
[![Join the chat at https://gitter.im/47deg/fetch](https://badges.gitter.im/47deg/fetch.svg)](https://gitter.im/47deg/fetch?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![Build Status](https://travis-ci.org/47deg/fetch.svg?branch=master)](https://travis-ci.org/47deg/fetch) [![codecov.io](http://codecov.io/github/47deg/fetch/coverage.svg?branch=master)](http://codecov.io/github/47deg/fetch?branch=master) [![Maven Central](https://img.shields.io/badge/maven%20central-0.6.1-green.svg)](https://oss.sonatype.org/#nexus-search;gav~com.47deg~fetch*) [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](https://raw.githubusercontent.com/47deg/fetch/master/LICENSE) [![Latest version](https://img.shields.io/badge/fetch-0.6.1-green.svg)](https://index.scala-lang.org/47deg/fetch) [![Scala.js](http://scala-js.org/assets/badges/scalajs-0.6.15.svg)](http://scala-js.org) [![GitHub Issues](https://img.shields.io/github/issues/47deg/fetch.svg)](https://github.com/47deg/fetch/issues)

[comment]: # (End Badges)

Expand Down Expand Up @@ -35,7 +35,7 @@ Or, if using Scala.js (0.6.x):

## Remote data

Fetch is a library for making access to data both simple & efficient. Fetch is especially useful when querying data that
Fetch is a library for making access to data both simple and efficient. Fetch is especially useful when querying data that
has a latency cost, such as databases or web services.

## Define your data sources
Expand All @@ -61,7 +61,7 @@ trait DataSource[F[_], Identity, Result]{
}
```

Returning `Concurrent` instances from the fetch methods allows us to specify if the fetch must run synchronously or asynchronously and use all the goodies available in `cats` and `cats-effect`.
Returning `Concurrent` instances from the fetch methods allows us to specify if the fetch must run synchronously or asynchronously, and use all the goodies available in `cats` and `cats-effect`.

We'll implement a dummy data source that can convert integers to strings. For convenience, we define a `fetchString` function that lifts identities (`Int` in our dummy data source) to a `Fetch`.

Expand Down Expand Up @@ -108,7 +108,7 @@ def fetchString[F[_] : Concurrent](n: Int): Fetch[F, String] =

Since `Fetch` relies on `Concurrent` from the `cats-effect` library, we'll need a runtime for executing our effects. We'll be using `IO` from `cats-effect` to run fetches, but you can use any type that has a `Concurrent` instance.

For executing `IO` we need a `ContextShift[IO]` used for running `IO` instances and a `Timer[IO]` that is used for scheduling, let's go ahead and create them, we'll use a `java.util.concurrent.ScheduledThreadPoolExecutor` with a couple of threads to run our fetches.
For executing `IO`, we need a `ContextShift[IO]` used for running `IO` instances and a `Timer[IO]` that is used for scheduling. Let's go ahead and create them. We'll use a `java.util.concurrent.ScheduledThreadPoolExecutor` with a couple of threads to run our fetches.

```scala
import java.util.concurrent._
Expand All @@ -130,39 +130,39 @@ def fetchOne[F[_] : Concurrent]: Fetch[F, String] =
fetchString(1)
```

Let's run it and wait for the fetch to complete, we'll use `IO#unsafeRunTimed` for testing purposes, which will run an `IO[A]` to `Option[A]` and return `None` if it didn't complete in time:
Let's run it and wait for the fetch to complete. We'll use `IO#unsafeRunTimed` for testing purposes, which will run an `IO[A]` to `Option[A]` and return `None` if it didn't complete in time:

```scala
import scala.concurrent.duration._
// import scala.concurrent.duration._

Fetch.run[IO](fetchOne).unsafeRunTimed(5.seconds)
// --> [65] One ToString 1
// <-- [65] One ToString 1
// --> [342] One ToString 1
// <-- [342] One ToString 1
// res0: Option[String] = Some(1)
```

As you can see in the previous example, the `ToStringSource` is queried once to get the value of 1.

## Batching

Multiple fetches to the same data source are automatically batched. For illustrating it, we are going to compose three independent fetch results as a tuple.
Multiple fetches to the same data source are automatically batched. For illustrating this, we are going to compose three independent fetch results as a tuple.

```scala
def fetchThree[F[_] : Concurrent]: Fetch[F, (String, String, String)] =
(fetchString(1), fetchString(2), fetchString(3)).tupled
```

When executing the above fetch, note how the three identities get batched and the data source is only queried once.
When executing the above fetch, note how the three identities get batched, and the data source is only queried once.

```scala
Fetch.run[IO](fetchThree).unsafeRunTimed(5.seconds)
// --> [65] Batch ToString NonEmptyList(1, 2, 3)
// <-- [65] Batch ToString NonEmptyList(1, 2, 3)
// --> [342] Batch ToString NonEmptyList(1, 2, 3)
// <-- [342] Batch ToString NonEmptyList(1, 2, 3)
// res1: Option[(String, String, String)] = Some((1,2,3))
```

Note that the `DataSource#batch` method is not mandatory, it will be implemented in terms of `DataSource#fetch` if you don't provide an implementation.
Note that the `DataSource#batch` method is not mandatory. It will be implemented in terms of `DataSource#fetch` if you don't provide an implementation.

```scala
object UnbatchedToString extends Data[Int, String] {
Expand Down Expand Up @@ -196,12 +196,12 @@ When executing the above fetch, note how the three identities get requested in p

```scala
Fetch.run[IO](fetchUnbatchedThree).unsafeRunTimed(5.seconds)
// --> [65] One UnbatchedToString 1
// --> [68] One UnbatchedToString 3
// --> [67] One UnbatchedToString 2
// <-- [65] One UnbatchedToString 1
// <-- [67] One UnbatchedToString 2
// <-- [68] One UnbatchedToString 3
// --> [342] One UnbatchedToString 1
// --> [344] One UnbatchedToString 2
// --> [343] One UnbatchedToString 3
// <-- [342] One UnbatchedToString 1
// <-- [344] One UnbatchedToString 2
// <-- [343] One UnbatchedToString 3
// res2: Option[(String, String, String)] = Some((1,2,3))
```

Expand Down Expand Up @@ -247,10 +247,10 @@ Note how the two independent data fetches run in parallel, minimizing the latenc

```scala
Fetch.run[IO](fetchMulti).unsafeRunTimed(5.seconds)
// --> [65] One ToString 1
// --> [66] One Length one
// <-- [65] One ToString 1
// <-- [66] One Length one
// --> [342] One ToString 1
// --> [345] One Length one
// <-- [342] One ToString 1
// <-- [345] One Length one
// res3: Option[(String, Int)] = Some((1,3))
```

Expand All @@ -267,12 +267,12 @@ def fetchTwice[F[_] : Concurrent]: Fetch[F, (String, String)] = for {
} yield (one, two)
```

While running it, notice that the data source is only queried once. The next time the identity is requested it's served from the cache.
While running it, notice that the data source is only queried once. The next time the identity is requested, it's served from the cache.

```scala
Fetch.run[IO](fetchTwice).unsafeRunTimed(5.seconds)
// --> [67] One ToString 1
// <-- [67] One ToString 1
// --> [344] One ToString 1
// <-- [344] One ToString 1
// res4: Option[(String, String)] = Some((1,1))
```

Expand All @@ -281,17 +281,18 @@ Fetch.run[IO](fetchTwice).unsafeRunTimed(5.seconds)

---

For more in-depth information take a look at our [documentation](http://47deg.github.io/fetch/docs.html).
For more in-depth information, take a look at our [documentation](http://47deg.github.io/fetch/docs.html).

## Fetch in the wild

If you wish to add your library here please consider a PR to include it in the list below.
If you wish to add your library here, please consider a PR to include it in the list below.

[comment]: # (Start Copyright)

# Copyright

Fetch is designed and developed by 47 Degrees

Copyright (C) 2016-2019 47 Degrees. <http://47deg.com>

[comment]: # (End Copyright)
[comment]: # (End Copyright)
22 changes: 11 additions & 11 deletions tut/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,7 @@ def println(msg: String): Unit = {

## Remote data

Fetch is a library for making access to data both simple & efficient. Fetch is especially useful when querying data that
Fetch is a library for making access to data both simple and efficient. Fetch is especially useful when querying data that
has a latency cost, such as databases or web services.

## Define your data sources
Expand All @@ -68,7 +68,7 @@ trait DataSource[F[_], Identity, Result]{
}
```

Returning `Concurrent` instances from the fetch methods allows us to specify if the fetch must run synchronously or asynchronously and use all the goodies available in `cats` and `cats-effect`.
Returning `Concurrent` instances from the fetch methods allows us to specify if the fetch must run synchronously or asynchronously, and use all the goodies available in `cats` and `cats-effect`.

We'll implement a dummy data source that can convert integers to strings. For convenience, we define a `fetchString` function that lifts identities (`Int` in our dummy data source) to a `Fetch`.

Expand Down Expand Up @@ -115,7 +115,7 @@ def fetchString[F[_] : Concurrent](n: Int): Fetch[F, String] =

Since `Fetch` relies on `Concurrent` from the `cats-effect` library, we'll need a runtime for executing our effects. We'll be using `IO` from `cats-effect` to run fetches, but you can use any type that has a `Concurrent` instance.

For executing `IO` we need a `ContextShift[IO]` used for running `IO` instances and a `Timer[IO]` that is used for scheduling, let's go ahead and create them, we'll use a `java.util.concurrent.ScheduledThreadPoolExecutor` with a couple of threads to run our fetches.
For executing `IO`, we need a `ContextShift[IO]` used for running `IO` instances and a `Timer[IO]` that is used for scheduling. Let's go ahead and create them. We'll use a `java.util.concurrent.ScheduledThreadPoolExecutor` with a couple of threads to run our fetches.

```tut:silent
import java.util.concurrent._
Expand All @@ -137,7 +137,7 @@ def fetchOne[F[_] : Concurrent]: Fetch[F, String] =
fetchString(1)
```

Let's run it and wait for the fetch to complete, we'll use `IO#unsafeRunTimed` for testing purposes, which will run an `IO[A]` to `Option[A]` and return `None` if it didn't complete in time:
Let's run it and wait for the fetch to complete. We'll use `IO#unsafeRunTimed` for testing purposes, which will run an `IO[A]` to `Option[A]` and return `None` if it didn't complete in time:

```tut:book
import scala.concurrent.duration._
Expand All @@ -149,20 +149,20 @@ As you can see in the previous example, the `ToStringSource` is queried once to

## Batching

Multiple fetches to the same data source are automatically batched. For illustrating it, we are going to compose three independent fetch results as a tuple.
Multiple fetches to the same data source are automatically batched. For illustrating this, we are going to compose three independent fetch results as a tuple.

```tut:silent
def fetchThree[F[_] : Concurrent]: Fetch[F, (String, String, String)] =
(fetchString(1), fetchString(2), fetchString(3)).tupled
```

When executing the above fetch, note how the three identities get batched and the data source is only queried once.
When executing the above fetch, note how the three identities get batched, and the data source is only queried once.

```tut:book
Fetch.run[IO](fetchThree).unsafeRunTimed(5.seconds)
```

Note that the `DataSource#batch` method is not mandatory, it will be implemented in terms of `DataSource#fetch` if you don't provide an implementation.
Note that the `DataSource#batch` method is not mandatory. It will be implemented in terms of `DataSource#fetch` if you don't provide an implementation.

```tut:silent
object UnbatchedToString extends Data[Int, String] {
Expand Down Expand Up @@ -255,7 +255,7 @@ def fetchTwice[F[_] : Concurrent]: Fetch[F, (String, String)] = for {
} yield (one, two)
```

While running it, notice that the data source is only queried once. The next time the identity is requested it's served from the cache.
While running it, notice that the data source is only queried once. The next time the identity is requested, it's served from the cache.

```tut:book
Fetch.run[IO](fetchTwice).unsafeRunTimed(5.seconds)
Expand All @@ -267,18 +267,18 @@ executor.shutdownNow()
```
---

For more in-depth information take a look at our [documentation](http://47deg.github.io/fetch/docs.html).
For more in-depth information, take a look at our [documentation](http://47deg.github.io/fetch/docs.html).

## Fetch in the wild

If you wish to add your library here please consider a PR to include it in the list below.
If you wish to add your library here, please consider a PR to include it in the list below.

[comment]: # (Start Copyright)

# Copyright

Fetch is designed and developed by 47 Degrees

Copyright (C) 2016-2018 47 Degrees. <http://47deg.com>
Copyright (C) 2016-2019 47 Degrees. <http://47deg.com>

[comment]: # (End Copyright)