releases: mutualize releases handling logic and move it to github class

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

src/github.ts

@@ -31,13 +31,14 @@ import {SummaryTableCell} from '@actions/core/lib/summary';
 import * as github from '@actions/github';
 import {GitHub as Octokit} from '@actions/github/lib/utils';
 import {Context} from '@actions/github/lib/context';
+import * as httpm from '@actions/http-client';
 import {TransferProgressEvent} from '@azure/core-http';
 import {BlobClient, BlobHTTPHeaders} from '@azure/storage-blob';
 import {jwtDecode, JwtPayload} from 'jwt-decode';
 
 import {Util} from './util';
 
-import {BuildSummaryOpts, GitHubActionsRuntimeToken, GitHubActionsRuntimeTokenAC, GitHubRepo, UploadArtifactOpts, UploadArtifactResponse} from './types/github';
+import {BuildSummaryOpts, GitHubActionsRuntimeToken, GitHubActionsRuntimeTokenAC, GitHubContentOpts, GitHubRelease, GitHubRepo, UploadArtifactOpts, UploadArtifactResponse} from './types/github';
 
 export interface GitHubOpts {
   token?: string;
@@ -54,6 +55,18 @@ export class GitHub {
     return this.octokit.rest.repos.get({...github.context.repo}).then(response => response.data as GitHubRepo);
   }
 
+  public async releases(name: string, opts: GitHubContentOpts): Promise<Record<string, GitHubRelease>> {
+    const url = `https://raw.githubusercontent.com/${opts.owner}/${opts.repo}/${opts.ref}/${opts.path}`;
+    const http: httpm.HttpClient = new httpm.HttpClient('docker-actions-toolkit');
+    const httpResp: httpm.HttpClientResponse = await http.get(url);
+    const dt = await httpResp.readBody();
+    const statusCode = httpResp.message.statusCode || 500;
+    if (statusCode >= 400) {
+      throw new Error(`Failed to get ${name} releases from ${url} with status code ${statusCode}: ${dt}`);
+    }
+    return <Record<string, GitHubRelease>>JSON.parse(dt);
+  }
+
   static get context(): Context {
     return github.context;
   }