feat(auth): add OAuth2 login (#276)

* feat(auth): add OAuth2 login with GitHub and Google

* chore(translations): add files for Japanese

* fix(auth): fix link function for GitHub

* feat(oauth): basic oidc implementation

* feat(oauth): oauth guard

* fix: disable image optimizations for logo to prevent caching issues with custom logos

* fix: memory leak while downloading large files

* chore(translations): update translations via Crowdin (#278)

* New translations en-us.ts (Japanese)

* New translations en-us.ts (Japanese)

* New translations en-us.ts (Japanese)

* release: 0.18.2

* doc(translations): Add Japanese README (#279)

* Added Japanese README.

* Added JAPANESE README link to README.md.

* Updated Japanese README.

* Updated Environment Variable Table.

* updated zh-cn README.

* feat(oauth): unlink account

* refactor(oauth): make providers extensible

* fix(oauth): fix discoveryUri error when toggle google-enabled

* feat(oauth): add microsoft and discord as oauth provider

* docs(oauth): update README.md

* docs(oauth): update oauth2-guide.md

* set password to null for new oauth users

* New translations en-us.ts (Japanese) (#281)

* chore(translations): add Polish files

* fix(oauth): fix random username and password

* feat(oauth): add totp

* fix(oauth): fix totp throttle

* fix(oauth): fix qrcode and remove comment

* feat(oauth): add error page

* fix(oauth): i18n of error page

* feat(auth): add OAuth2 login

* fix(auth): fix link function for GitHub

* feat(oauth): basic oidc implementation

* feat(oauth): oauth guard

* feat(oauth): unlink account

* refactor(oauth): make providers extensible

* fix(oauth): fix discoveryUri error when toggle google-enabled

* feat(oauth): add microsoft and discord as oauth provider

* docs(oauth): update README.md

* docs(oauth): update oauth2-guide.md

* set password to null for new oauth users

* fix(oauth): fix random username and password

* feat(oauth): add totp

* fix(oauth): fix totp throttle

* fix(oauth): fix qrcode and remove comment

* feat(oauth): add error page

* fix(oauth): i18n of error page

* refactor: return null instead of `false` in `getIdOfCurrentUser` functiom

* feat: show original oauth error if available

* refactor: run formatter

* refactor(oauth): error message i18n

* refactor(oauth): make OAuth token available
someone may use it (to revoke token or get other info etc.)
also improved the i18n message

* chore(oauth): remove unused import

* chore: add database migration

* fix: missing python installation for nanoid

---------

Co-authored-by: Elias Schneider <login@eliasschneider.com>
Co-authored-by: ふうせん <10260662+fusengum@users.noreply.github.com>

backend/src/oauth/provider/github.provider.ts

@@ -0,0 +1,110 @@
+import { OAuthProvider, OAuthToken } from "./oauthProvider.interface";
+import { OAuthCallbackDto } from "../dto/oauthCallback.dto";
+import { OAuthSignInDto } from "../dto/oauthSignIn.dto";
+import { ConfigService } from "../../config/config.service";
+import fetch from "node-fetch";
+import { BadRequestException, Injectable } from "@nestjs/common";
+
+@Injectable()
+export class GitHubProvider implements OAuthProvider<GitHubToken> {
+  constructor(private config: ConfigService) {}
+
+  getAuthEndpoint(state: string): Promise<string> {
+    return Promise.resolve(
+      "https://github.com/login/oauth/authorize?" +
+        new URLSearchParams({
+          client_id: this.config.get("oauth.github-clientId"),
+          redirect_uri:
+            this.config.get("general.appUrl") + "/api/oauth/callback/github",
+          state: state,
+          scope: "user:email",
+        }).toString(),
+    );
+  }
+
+  async getToken(query: OAuthCallbackDto): Promise<OAuthToken<GitHubToken>> {
+    const res = await fetch(
+      "https://github.com/login/oauth/access_token?" +
+        new URLSearchParams({
+          client_id: this.config.get("oauth.github-clientId"),
+          client_secret: this.config.get("oauth.github-clientSecret"),
+          code: query.code,
+        }).toString(),
+      {
+        method: "post",
+        headers: {
+          Accept: "application/json",
+        },
+      },
+    );
+    const token: GitHubToken = await res.json();
+    return {
+      accessToken: token.access_token,
+      tokenType: token.token_type,
+      rawToken: token,
+    };
+  }
+
+  async getUserInfo(token: OAuthToken<GitHubToken>): Promise<OAuthSignInDto> {
+    const user = await this.getGitHubUser(token);
+    if (!token.scope.includes("user:email")) {
+      throw new BadRequestException("No email permission granted");
+    }
+    const email = await this.getGitHubEmail(token);
+    if (!email) {
+      throw new BadRequestException("No email found");
+    }
+
+    return {
+      provider: "github",
+      providerId: user.id.toString(),
+      providerUsername: user.name ?? user.login,
+      email,
+    };
+  }
+
+  private async getGitHubUser(
+    token: OAuthToken<GitHubToken>,
+  ): Promise<GitHubUser> {
+    const res = await fetch("https://api.github.com/user", {
+      headers: {
+        Accept: "application/vnd.github+json",
+        Authorization: `${token.tokenType ?? "Bearer"} ${token.accessToken}`,
+      },
+    });
+    return (await res.json()) as GitHubUser;
+  }
+
+  private async getGitHubEmail(
+    token: OAuthToken<GitHubToken>,
+  ): Promise<string | undefined> {
+    const res = await fetch("https://api.github.com/user/public_emails", {
+      headers: {
+        Accept: "application/vnd.github+json",
+        Authorization: `${token.tokenType ?? "Bearer"} ${token.accessToken}`,
+      },
+    });
+    const emails = (await res.json()) as GitHubEmail[];
+    return emails.find((e) => e.primary && e.verified)?.email;
+  }
+}
+
+export interface GitHubToken {
+  access_token: string;
+  token_type: string;
+  scope: string;
+}
+
+export interface GitHubUser {
+  login: string;
+  id: number;
+  name?: string;
+  email?: string; // this filed seems only return null
+}
+
+export interface GitHubEmail {
+  email: string;
+  primary: boolean;
+  verified: boolean;
+  visibility: string | null;
+}