Support retrieving a blob (#494)

Author: georgeorfanidi

docs/docs/git_data.md

@@ -14,6 +14,7 @@ with Github4s, you can:
 - [Update a Reference](#update-a-reference)
 - [Get a Commit](#get-a-commit)
 - [Create a Commit](#create-a-commit)
+- [Get a Blob](#get-a-blob)
 - [Create a Blob](#create-a-blob)
 - [Get a Tree](#get-a-tree)
 - [Create a Tree](#create-a-tree)
@@ -191,6 +192,26 @@ See [the API doc](https://developer.github.com/v3/git/commits/#create-a-commit)
 
 ## Blobs
 
+### Get a Blob
+
+You can get a blob using `getBlob`; it takes as arguments:
+
+- the repository coordinates (`owner` and `name` of the repository).
+- `sha`: the sha of the blob.
+
+```scala mdoc:compile-only
+val getBlob = gh.gitData.getBlob("47degrees", "github4s", "d3b048c1f500ee5450e5d7b3d1921ed3e7645891")
+val response = getBlob.unsafeRunSync()
+response.result match {
+  case Left(e) => println(s"Something went wrong: ${e.getMessage}")
+  case Right(r) => println(r)
+}
+```
+
+The `result` on the right is the corresponding [BlobContent][gitdata-scala].
+
+See [the API doc](https://developer.github.com/v3/git/blobs/#get-a-blob) for full reference.
+
 ### Create a Blob
 
 You can create a blob using `createBlob`; it takes as arguments:

github4s/src/main/scala/github4s/Decoders.scala

@@ -265,6 +265,7 @@ object Decoders {
   implicit val decoderCombinedStatus: Decoder[CombinedStatus] = deriveDecoder[CombinedStatus]
   implicit val decoderLabel: Decoder[Label]                   = deriveDecoder[Label]
   implicit val decoderContent: Decoder[Content]               = deriveDecoder[Content]
+  implicit val decoderBlobContent: Decoder[BlobContent]       = deriveDecoder[BlobContent]
   implicit val decoderSubscription: Decoder[Subscription]     = deriveDecoder[Subscription]
   implicit val decoderAuthorization: Decoder[Authorization]   = deriveDecoder[Authorization]
   implicit val decoderOAuthToken: Decoder[OAuthToken]         = deriveDecoder[OAuthToken]

github4s/src/main/scala/github4s/algebras/GitData.scala

@@ -130,6 +130,22 @@ trait GitData[F[_]] {
       headers: Map[String, String] = Map()
   ): F[GHResponse[RefCommit]]
 
+  /**
+   * Get a Blob by sha
+   *
+   * @param owner of the repo
+   * @param repo name of the repo
+   * @param fileSha to identify the blob
+   * @param headers optional user headers to include in the request
+   * @return a GHResponse with BlobContent
+   */
+  def getBlob(
+      owner: String,
+      repo: String,
+      fileSha: String,
+      headers: Map[String, String] = Map()
+  ): F[GHResponse[BlobContent]]
+
   /**
    * Create a new Blob
    *

github4s/src/main/scala/github4s/domain/GitData.scala

@@ -83,6 +83,14 @@ final case class NewCommitRequest(
     author: Option[RefAuthor]
 )
 
+final case class BlobContent(
+    content: Option[String],
+    encoding: Option[String],
+    url: String,
+    sha: String,
+    size: Int
+)
+
 final case class NewBlobRequest(content: String, encoding: Option[String])
 
 final case class NewTreeRequest(base_tree: Option[String], tree: List[TreeData])

github4s/src/main/scala/github4s/interpreters/GitDataInterpreter.scala

@@ -93,6 +93,14 @@ class GitDataInterpreter[F[_]](implicit client: HttpClient[F], accessToken: Opti
       NewCommitRequest(message, tree, parents, author)
     )
 
+  override def getBlob(
+      owner: String,
+      repo: String,
+      fileSha: String,
+      headers: Map[String, String]
+  ): F[GHResponse[BlobContent]] =
+    client.get[BlobContent](accessToken, s"repos/$owner/$repo/git/blobs/$fileSha", headers)
+
   override def createBlob(
       owner: String,
       repo: String,

github4s/src/test/scala/github4s/integration/ReposSpec.scala

@@ -16,8 +16,8 @@
 
 package github4s.integration
 
-import cats.effect.IO
 import cats.data.NonEmptyList
+import cats.effect.{IO, Resource}
 import github4s.GHError.NotFoundError
 import github4s.Github
 import github4s.domain._
@@ -133,6 +133,44 @@ trait ReposSpec extends BaseIntegrationSpec {
     response.statusCode shouldBe okStatusCode
   }
 
+  "Repos >> GetContents" should "have the same contents with getBlob using fileSha" taggedAs Integration in {
+
+    val blobResponseFileContent = for {
+      client <- clientResource
+      res = Github[IO](client, accessToken)
+
+      fileContentsIO = res.repos.getContents(
+        owner = validRepoOwner,
+        repo = validRepoName,
+        path = validFilePath,
+        headers = headerUserAgent
+      )
+
+      fileContentsResponse <- Resource.liftF(fileContentsIO)
+
+      fileContentsEither = fileContentsResponse.result
+
+      fileContents <- Resource.liftF(IO.fromEither(fileContentsEither))
+
+      blobContentIO = res.gitData.getBlob(
+        owner = validRepoOwner,
+        repo = validRepoName,
+        fileSha = fileContents.head.sha,
+        headers = headerUserAgent
+      )
+
+      blobContentResponse <- Resource.liftF(blobContentIO)
+
+    } yield (blobContentResponse, fileContents.head)
+
+    val (blobContentResponse, fileContent) = blobResponseFileContent
+      .use(a => IO.apply(a))
+      .unsafeRunSync()
+
+    testIsRight[BlobContent](blobContentResponse, _.content.shouldBe(fileContent.content))
+    blobContentResponse.statusCode shouldBe okStatusCode
+  }
+
   it should "return error when an invalid path is passed" taggedAs Integration in {
     val response = clientResource
       .use { client =>

github4s/src/test/scala/github4s/unit/GitDataSpec.scala

@@ -144,6 +144,22 @@ class GitDataSpec extends BaseSpec {
 
   }
 
+  "GitData.getBlob" should "call to httpClient.post with the right parameters" in {
+
+    val response: IO[GHResponse[BlobContent]] =
+      IO(
+        GHResponse(BlobContent(None, None, "", invalidFileSha, 0).asRight, okStatusCode, Map.empty)
+      )
+
+    implicit val httpClientMock = httpClientMockGet[BlobContent](
+      url = s"repos/$validRepoOwner/$validRepoName/git/blobs/$invalidFileSha",
+      response = response
+    )
+    val gitData = new GitDataInterpreter[IO]
+    gitData.getBlob(validRepoOwner, validRepoName, invalidFileSha, headerUserAgent)
+
+  }
+
   "GitData.getTree" should "call to httpClient.get with the right parameters" in {
 
     val response: IO[GHResponse[TreeResult]] =

github4s/src/test/scala/github4s/utils/TestData.scala

@@ -113,6 +113,7 @@ trait TestData {
 
   val validTreeSha   = "827efc6d56897b048c772eb4087f854f46256132"
   val invalidTreeSha = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+  val invalidFileSha = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
 
   val validTagTitle = "v0.1.1"
   val validTagSha   = "c3d0be41ecbe669545ee3e94d31ed9a4bc91ee3c"