add download apis to stream zip from blob storage

packages/artifact/src/artifact.ts

@@ -1,10 +1,10 @@
 import {ArtifactClient, Client} from './internal/client'
-import {UploadOptions, UploadResponse} from './internal/shared/interfaces'
 
 /**
  * Exported functionality that we want to expose for any users of @actions/artifact
  */
-export {ArtifactClient, UploadOptions, UploadResponse}
+export * from './internal/shared/interfaces'
+export {ArtifactClient}
 
 export function create(): ArtifactClient {
   return Client.create()

packages/artifact/src/internal/download/download-artifact.ts

@@ -1,7 +1,52 @@
+import path from 'path'
+import fs from 'fs/promises'
+import {PathLike} from 'fs'
+import github from '@actions/github'
+import core from '@actions/core'
+import httpClient from '@actions/http-client'
+import unzipper from 'unzipper'
 import {
   DownloadArtifactOptions,
   DownloadArtifactResponse
 } from '../shared/interfaces'
+import {getUserAgentString} from '../shared/user-agent'
+
+const scrubQueryParameters = (url: string): string => {
+  const parsed = new URL(url)
+  parsed.search = ''
+  return parsed.toString()
+}
+
+async function exists(path: string): Promise<boolean> {
+  try {
+    await fs.access(path)
+    return true
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+      return false
+    } else {
+      throw error
+    }
+  }
+}
+
+async function streamExtract(url: string, directory: PathLike): Promise<void> {
+  const client = new httpClient.HttpClient(getUserAgentString())
+  const response = await client.get(url)
+
+  if (response.message.statusCode !== 200) {
+    throw new Error(
+      `Unexpected HTTP response from blob storage: ${response.message.statusCode} ${response.message.statusMessage}`
+    )
+  }
+
+  return new Promise((resolve, reject) => {
+    response.message
+      .pipe(unzipper.Extract({path: directory}))
+      .on('finish', resolve)
+      .on('error', reject)
+  })
+}
 
 export async function downloadArtifact(
   artifactId: number,
@@ -10,5 +55,54 @@ export async function downloadArtifact(
   token: string,
   options?: DownloadArtifactOptions
 ): Promise<DownloadArtifactResponse> {
-  throw new Error('Not implemented')
+  let downloadPath = options?.path || process.cwd() // TODO: make this align with GITHUB_WORKSPACE
+  if (options?.createArtifactFolder) {
+    downloadPath = path.join(downloadPath, 'my-artifact') // TODO: need to pass artifact name
+  }
+
+  if (!(await exists(downloadPath))) {
+    core.debug(`Creating artifact folder: ${downloadPath}`)
+    await fs.mkdir(downloadPath, {recursive: true})
+  } else {
+    core.warning(`Artifact folder already exists: ${downloadPath}`)
+  }
+
+  const api = github.getOctokit(token)
+
+  core.info(
+    `Downloading artifact ${artifactId} from ${repositoryOwner}/${repositoryName}`
+  )
+
+  const {headers, status} = await api.rest.actions.downloadArtifact({
+    owner: repositoryOwner,
+    repo: repositoryName,
+    artifact_id: artifactId,
+    archive_format: 'zip',
+    request: {
+      redirect: 'manual'
+    }
+  })
+
+  if (status !== 302) {
+    throw new Error(`Unable to download artifact. Unexpected status: ${status}`)
+  }
+
+  const {location} = headers
+  if (!location) {
+    throw new Error(`Unable to redirect to artifact download url`)
+  }
+
+  core.info(
+    `Redirecting to blob download url: ${scrubQueryParameters(location)}`
+  )
+
+  try {
+    core.info(`Starting download of artifact to: ${downloadPath}`)
+    await streamExtract(location, downloadPath)
+    core.info(`Artifact download completed successfully.`)
+  } catch (error) {
+    throw new Error(`Unable to download and extract artifact: ${error.message}`)
+  }
+
+  return {success: true}
 }