github-service-paginated.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Observable, forkJoin, of } from 'rxjs';
import { switchMap, map, catchError } from 'rxjs/operators';

@Injectable({
  providedIn: 'root',
})
export class GithubService {
  private apiUrl = 'https://api.github.com';
  private token = 'your-personal-access-token'; // Optional

  constructor(private http: HttpClient) {}

  // Get user's organizations
  getUserOrganizations(username: string): Observable<any[]> {
    const headers = this.getAuthHeaders();
    return this.http.get<any[]>(`${this.apiUrl}/users/${username}/orgs`, { headers });
  }

  // Get repositories for an organization with pagination
  getOrganizationRepos(org: string): Observable<any[]> {
    const headers = this.getAuthHeaders();
    const perPage = 100; // Max results per page

    // Fetch the first page to determine total count
    return this.http.get<any[]>(`${this.apiUrl}/orgs/${org}/repos?per_page=${perPage}&page=1`, { observe: 'response', headers }).pipe(
      switchMap((response) => {
        const repos = response.body || [];
        const linkHeader = response.headers.get('link');
        const totalPages = this.getTotalPagesFromLinkHeader(linkHeader);

        if (totalPages <= 1) {
          return of(repos); // If there's only one page, return the repos directly
        }

        // Generate requests for remaining pages
        const pageRequests: Observable<any[]>[] = [];
        for (let i = 2; i <= totalPages; i++) {
          pageRequests.push(
            this.http.get<any[]>(`${this.apiUrl}/orgs/${org}/repos?per_page=${perPage}&page=${i}`, { headers })
          );
        }

        return forkJoin(pageRequests).pipe(
          map((pages) => repos.concat(...pages.flat())) // Combine all pages into a single array
        );
      })
    );
  }

  // Get all template repositories from all organizations
  getTemplateRepos(username: string): Observable<any[]> {
    return this.getUserOrganizations(username).pipe(
      map((orgs) => orgs.map((org) => org.login)), // Extract organization logins
      switchMap((orgLogins) =>
        forkJoin(orgLogins.map((org) => this.getOrganizationRepos(org))).pipe(
          map((allRepos) => allRepos.flat().filter((repo) => repo.is_template)) // Filter for template repos
        )
      ),
      catchError((error) => {
        console.error('Error fetching template repositories:', error);
        return of([]); // Return an empty array on error
      })
    );
  }

  private getAuthHeaders(): HttpHeaders {
    return this.token ? new HttpHeaders({ Authorization: `Bearer ${this.token}` }) : new HttpHeaders();
  }

  // Parse the `link` header to get the total number of pages
  private getTotalPagesFromLinkHeader(linkHeader: string | null): number {
    if (!linkHeader) {
      return 1;
    }

    const match = linkHeader.match(/&page=(\d+)>; rel="last"/);
    return match ? parseInt(match[1], 10) : 1;
  }
}

github-service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Observable, forkJoin } from 'rxjs';
import { map } from 'rxjs/operators';

@Injectable({
  providedIn: 'root',
})
export class GithubService {
  private apiUrl = 'https://api.github.com';
  private token = 'your-personal-access-token'; // Optional

  constructor(private http: HttpClient) {}

  // Get user's organizations
  getUserOrganizations(username: string): Observable<any[]> {
    const headers = this.getAuthHeaders();
    return this.http.get<any[]>(`${this.apiUrl}/users/${username}/orgs`, { headers });
  }

  // Get repositories for an organization
  getOrganizationRepos(org: string): Observable<any[]> {
    const headers = this.getAuthHeaders();
    return this.http.get<any[]>(`${this.apiUrl}/orgs/${org}/repos`, { headers });
  }

  // Get all template repositories from all organizations
  getTemplateRepos(username: string): Observable<any[]> {
    return this.getUserOrganizations(username).pipe(
      map((orgs) => orgs.map((org) => org.login)), // Extract organization logins
      map((orgLogins) =>
        orgLogins.map((org) => this.getOrganizationRepos(org)) // Create observables for each org's repos
      ),
      map((orgRequests) => forkJoin(orgRequests)), // Combine all org requests
      map((orgsRepos$: Observable<any[]>) =>
        orgsRepos$.pipe(
          map((orgRepos) =>
            orgRepos.flat().filter((repo: any) => repo.is_template) // Filter template repos
          )
        )
      ),
      (orgsRepos$) => orgsRepos$.flat() // Flatten the array of repos
    );
  }

  private getAuthHeaders(): HttpHeaders {
    return this.token ? new HttpHeaders({ Authorization: `Bearer ${this.token}` }) : new HttpHeaders();
  }
}