Implement allow_duplicate

Introduce a new option `allow_duplicate` (`true` by default). If it is
`true` the behavior keeps the same. When it is `false`, the review is
only sent if there not already a review by `github-actions` with the
same body and type.

Closes AndrewMusgrave#39

README.md

@@ -27,14 +27,16 @@ jobs:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           event: APPROVE
           body: 'Thank you dependabot 🎊'
+          allow_duplicate: false
 ```
 
 ## Workflow options
 
 These are the options recommended to be changed. For more detailed explanation of the workflow file, check out the [GitHub documentation](https://help.github.com/en/articles/configuring-a-workflow#creating-a-workflow-file).
 
-| Setting      | Description                                                                                | Values                                           |
-| ------------ | ------------------------------------------------------------------------------------------ | ------------------------------------------------ |
-| `event`      | The event to perform on the pull request review.                                           | APPROVE \| COMMENT \| DISMISS \| REQUEST_CHANGES |
-| `body`       | The contents of the review body comment. Required when event is COMMENT or REQUEST_CHANGES | String                                           |
-| `repo-token` | The personal access token                                                                  | `${{ secrets.GITHUB_TOKEN }}`                    |
+| Setting           | Description                                                                                | Values                                           |
+| ----------------- | ------------------------------------------------------------------------------------------ | ------------------------------------------------ |
+| `event`           | The event to perform on the pull request review.                                           | APPROVE \| COMMENT \| DISMISS \| REQUEST_CHANGES |
+| `body`            | The contents of the review body comment. Required when event is COMMENT or REQUEST_CHANGES | String                                           |
+| `allow_duplicate` | The review is sent more than once. `true` by default.                                      | `true` or `false`                                |
+| `repo-token`      | The personal access token                                                                  | `${{ secrets.GITHUB_TOKEN }}`                    |

action.yml

@@ -13,6 +13,8 @@ inputs:
     default: 'APPROVE'
   body:
     description: 'The contents of the review body comment. Required when event is COMMENT or REQUEST_CHANGES.'
+  allow_duplicate:
+    default: true
   repo-token:
     description: 'The GH_TOKEN secret can be passed in using {{ secrets.GH_TOKEN }}'
     required: true

index.ts

@@ -1,9 +1,78 @@
 import * as core from '@actions/core';
 import * as github from '@actions/github';
 
+/** Returns true if any review in the reviews array has author's login
+'github-actions' and the body given as parameter  */
+function isAnyDuplicatedReview(reviews: Array<any>, body: string): boolean {
+  for (let review of reviews) {
+    if(review.author.login === 'github-actions' && review.body === body){
+      core.info('Duplicated review');
+      return true;
+    }
+  }
+  core.info('No duplicated review');
+  return false;
+}
+
+/** Gets the PR reviews by querying the GitHub API (GraphQL) and calls
+isAnyDuplicatedReview to know if any of them is a duplicate */
+async function existsDuplicatedReview(octokit: any, reviewState: string, pullRequest: any, body: string): Promise<boolean | undefined > {
+  const repo = pullRequest.base.repo
+  const query = `
+    query {
+    repository(owner: "${repo.owner.login}", name: "${repo.name}") {
+      pullRequest(number: ${pullRequest.number}) {
+        reviews(last: 100, states: ${reviewState}) {
+          nodes {
+            author {
+              login
+            }
+            body
+          }
+        }
+      }
+    }
+  }`;
+
+  try {
+    const { repository } = await octokit.graphql(query, {});
+    const reviews = repository.pullRequest.reviews.nodes
+    return isAnyDuplicatedReview(reviews, body);
+  }
+  catch (err) {
+    core.error(`${err} ${query}`);
+    core.setFailed(err.message);
+  }
+}
+
+/** Send the review if there is not a duplicate or if duplicates are allowes */
+async function sendReview(octokit: any, reviewState: string, pullRequest: any, body: string, allow_duplicate: boolean): Promise<void> {
+  if(allow_duplicate || !(await existsDuplicatedReview(octokit, reviewState, pullRequest, body))) {
+    const query = `
+      mutation {
+        addPullRequestReview(input: {
+        pullRequestId: "${(<any>pullRequest)['node_id']}",
+        event: ${requestEvent},
+        body: "${body}"
+      }) {clientMutationId}
+    }`;
+    octokit.graphql(query).catch((err: Error) => {
+      core.error(`${err} ${query}`);
+      core.setFailed(err.message);
+    });
+  }
+}
+
 const token = core.getInput('repo-token');
 const requestEvent = core.getInput('event');
 const body = core.getInput('body');
+const allow_duplicate = core.getInput('allow_duplicate').toUpperCase() === 'TRUE';
+const pullRequestReviewState : Record<string, string> = {
+  APPROVE: 'APPROVED',
+  COMMENT: 'COMMENTED',
+  DISMISS: 'DISMISSED',
+  REQUEST_CHANGES: 'CHANGES_REQUESTED'
+}
 
 const octokit = github.getOctokit(token)
 
@@ -20,16 +89,6 @@ if (!pullRequest) {
   core.setFailed('This action is meant to be ran on pull requests');
 }
 
-const query = `
-mutation {
-  addPullRequestReview(input: {
-    pullRequestId: "${(<any>pullRequest)['node_id']}",
-    event: ${requestEvent},
-    body: "${body}"
-  }) {clientMutationId}
-}`;
-
-octokit.graphql(query).catch((err) => {
-  core.error(err);
-  core.setFailed(err.message);
-});
+
+const reviewState = pullRequestReviewState[requestEvent];
+sendReview(octokit, reviewState, pullRequest, body, allow_duplicate);

package.json

@@ -25,7 +25,8 @@
   "homepage": "https://github.com/andrewmusgrave/automatic-pull-request-review#readme",
   "dependencies": {
     "@actions/core": "^1.2.7",
-    "@actions/github": "^4.0.0"
+    "@actions/github": "^4.0.0",
+    "@octokit/webhooks": "^9.6.1"
   },
   "devDependencies": {
     "@types/node": "^12.7.4",
@@ -41,4 +42,4 @@
       "pre-commit": "npm run build && git add ./dist/index.js"
     }
   }
-}
+}