PrestamoService

Overview

The PrestamoService handles all operations related to book loans (préstamos) including requesting loans, listing loans, and managing loan approvals/rejections. It provides different methods for regular users and administrators. Location: src/app/core/services/prestamo.ts

Constructor

private http = inject(HttpClient);

Uses Angular’s inject() function to obtain HttpClient instance.

Properties

string

default:"${environment.apiUrl}/prestamos"

Base URL for prestamo endpoints, configured from environment settings.

Methods

solicitar()

Requests a loan for a specific book. Available to authenticated users.

solicitar(libroId: number): Observable<any>

number

required

The unique identifier of the book to borrow

Returns: Observable<any> - Plain text response from server Response Type: Text (uses responseType: 'text') Example:

const bookId = 42;

this.prestamoService.solicitar(bookId).subscribe({
  next: (response) => {
    console.log('Loan requested:', response);
    alert('Solicitud de préstamo enviada exitosamente');
  },
  error: (error) => {
    if (error.status === 400) {
      alert('El libro no está disponible');
    } else {
      console.error('Error requesting loan:', error);
    }
  }
});

API Endpoint: POST ${apiUrl}/solicitar/{libroId} Request Body: Empty object {} Use Case: When a user wants to borrow a book from the catalog

getAll()

Retrieves all loan requests from all users. Admin-only endpoint.

getAll(): Observable<Prestamo[]>

Returns: Observable<Prestamo[]> - Array of all loan requests

array

Array of loan objects

number

Unique loan identifier

string

Date when the loan was requested (ISO 8601 format)

string

Date when the book was returned (if applicable)

string

Loan status: “PENDIENTE”, “APROBADO”, or “RECHAZADO”

Libro

Complete book object (id, titulo, portada, genero, autores, etc.)

any

User information from Spring Boot backend

Example:

// Admin component
this.prestamoService.getAll().subscribe({
  next: (prestamos) => {
    console.log(`Found ${prestamos.length} loan requests`);
    this.allLoans = prestamos;
    
    // Filter by status
    this.pendingLoans = prestamos.filter(p => p.estado === 'PENDIENTE');
    this.approvedLoans = prestamos.filter(p => p.estado === 'APROBADO');
  },
  error: (error) => {
    console.error('Error fetching loans:', error);
  }
});

API Endpoint: GET ${apiUrl}/todos Authorization: Requires ROLE_ADMIN

getMisPrestamos()

Retrieves loan requests for the currently authenticated user.

getMisPrestamos(): Observable<Prestamo[]>

Returns: Observable<Prestamo[]> - Array of current user’s loan requests Example:

// User component
this.prestamoService.getMisPrestamos().subscribe({
  next: (misPrestamos) => {
    console.log(`You have ${misPrestamos.length} loan requests`);
    this.myLoans = misPrestamos;
    
    // Show status to user
    misPrestamos.forEach(prestamo => {
      console.log(`${prestamo.libro.titulo} - ${prestamo.estado}`);
    });
  },
  error: (error) => {
    console.error('Error fetching my loans:', error);
  }
});

API Endpoint: GET ${apiUrl}/mios Authorization: Requires authentication (ROLE_USER or ROLE_ADMIN) Use Case: Displaying user’s loan history and current requests

aprobar()

Approves a pending loan request. Admin-only operation.

aprobar(id: number): Observable<any>

number

required

The unique identifier of the loan to approve

Returns: Observable<any> - Plain text response from server Response Type: Text (uses responseType: 'text') Example:

const prestamoId = 15;

this.prestamoService.aprobar(prestamoId).subscribe({
  next: (response) => {
    console.log('Loan approved:', response);
    alert('Préstamo aprobado exitosamente');
    this.loadPendingLoans(); // Refresh the list
  },
  error: (error) => {
    console.error('Error approving loan:', error);
  }
});

API Endpoint: POST ${apiUrl}/aprobar/{id} Request Body: Empty object {} Authorization: Requires ROLE_ADMIN Behavior: Changes loan status from PENDIENTE to APROBADO

rechazar()

Rejects a pending loan request. Admin-only operation.

rechazar(id: number): Observable<any>

number

required

The unique identifier of the loan to reject

Returns: Observable<any> - Plain text response from server Response Type: Text (uses responseType: 'text') Example:

const prestamoId = 15;

if (confirm('¿Está seguro de rechazar este préstamo?')) {
  this.prestamoService.rechazar(prestamoId).subscribe({
    next: (response) => {
      console.log('Loan rejected:', response);
      alert('Préstamo rechazado');
      this.loadPendingLoans(); // Refresh the list
    },
    error: (error) => {
      console.error('Error rejecting loan:', error);
    }
  });
}

API Endpoint: POST ${apiUrl}/rechazar/{id} Request Body: Empty object {} Authorization: Requires ROLE_ADMIN Behavior: Changes loan status from PENDIENTE to RECHAZADO

Complete Usage Examples

User Component (Request and View Loans)

import { Component, OnInit, inject } from '@angular/core';
import { PrestamoService } from '../core/services/prestamo';
import { Prestamo } from '../core/models/prestamo';

@Component({
  selector: 'app-my-loans',
  templateUrl: './my-loans.html'
})
export class MyLoansComponent implements OnInit {
  prestamoService = inject(PrestamoService);
  myLoans: Prestamo[] = [];
  loading = false;

  ngOnInit() {
    this.loadMyLoans();
  }

  loadMyLoans() {
    this.loading = true;
    this.prestamoService.getMisPrestamos().subscribe({
      next: (prestamos) => {
        this.myLoans = prestamos;
        this.loading = false;
      },
      error: (err) => {
        console.error('Error loading loans:', err);
        this.loading = false;
      }
    });
  }

  requestLoan(libroId: number) {
    this.prestamoService.solicitar(libroId).subscribe({
      next: (response) => {
        alert('Préstamo solicitado exitosamente');
        this.loadMyLoans(); // Refresh to show new request
      },
      error: (err) => {
        alert('Error al solicitar préstamo');
      }
    });
  }

  getStatusClass(estado: string): string {
    switch(estado) {
      case 'PENDIENTE': return 'badge-warning';
      case 'APROBADO': return 'badge-success';
      case 'RECHAZADO': return 'badge-danger';
      default: return 'badge-secondary';
    }
  }
}

Admin Component (Manage All Loans)

import { Component, OnInit, inject } from '@angular/core';
import { PrestamoService } from '../core/services/prestamo';
import { Prestamo } from '../core/models/prestamo';

@Component({
  selector: 'app-prestamo-list',
  templateUrl: './prestamo-list.html'
})
export class PrestamoListComponent implements OnInit {
  prestamoService = inject(PrestamoService);
  prestamos: Prestamo[] = [];
  filteredPrestamos: Prestamo[] = [];
  selectedFilter: string = 'TODOS';

  ngOnInit() {
    this.loadPrestamos();
  }

  loadPrestamos() {
    this.prestamoService.getAll().subscribe({
      next: (data) => {
        this.prestamos = data;
        this.applyFilter();
      },
      error: (err) => {
        console.error('Error loading loans:', err);
      }
    });
  }

  applyFilter() {
    if (this.selectedFilter === 'TODOS') {
      this.filteredPrestamos = this.prestamos;
    } else {
      this.filteredPrestamos = this.prestamos.filter(
        p => p.estado === this.selectedFilter
      );
    }
  }

  aprobarPrestamo(id: number) {
    this.prestamoService.aprobar(id).subscribe({
      next: () => {
        alert('Préstamo aprobado');
        this.loadPrestamos();
      },
      error: (err) => {
        console.error('Error approving loan:', err);
      }
    });
  }

  rechazarPrestamo(id: number) {
    if (confirm('¿Rechazar este préstamo?')) {
      this.prestamoService.rechazar(id).subscribe({
        next: () => {
          alert('Préstamo rechazado');
          this.loadPrestamos();
        },
        error: (err) => {
          console.error('Error rejecting loan:', err);
        }
      });
    }
  }
}

Data Model

Prestamo Interface

import { Libro } from './libro';

export interface Prestamo {
  id: number;
  fechaSolicitud: string;
  fechaDevolucion?: string;
  estado: 'PENDIENTE' | 'APROBADO' | 'RECHAZADO';
  libro: Libro;
  usuario: any; // Complete user object from Spring Boot
}

Estado (Status) Values

string

Loan request is awaiting admin approval

string

Loan has been approved by an administrator

string

Loan has been rejected by an administrator

Error Handling

Common error scenarios:

this.prestamoService.solicitar(libroId).subscribe({
  next: (response) => { /* success */ },
  error: (error) => {
    if (error.status === 400) {
      console.error('Book not available or already requested');
    } else if (error.status === 401) {
      console.error('Authentication required');
    } else if (error.status === 403) {
      console.error('Access forbidden');
    } else if (error.status === 404) {
      console.error('Book not found');
    } else {
      console.error('Unexpected error:', error);
    }
  }
});

Authorization Requirements

Method	Required Role	Description
`solicitar()`	ROLE_USER or ROLE_ADMIN	Any authenticated user
`getMisPrestamos()`	ROLE_USER or ROLE_ADMIN	Any authenticated user
`getAll()`	ROLE_ADMIN	Admin only
`aprobar()`	ROLE_ADMIN	Admin only
`rechazar()`	ROLE_ADMIN	Admin only

Services

Guards

Models

Components

Interceptors

Overview

Constructor

Properties

Methods

solicitar()

getAll()

getMisPrestamos()

aprobar()

rechazar()

Complete Usage Examples

User Component (Request and View Loans)

Admin Component (Manage All Loans)

Data Model

Prestamo Interface

Estado (Status) Values

Error Handling

Authorization Requirements

See Also

​Overview

​Constructor

​Properties

​Methods

​solicitar()

​getAll()

​getMisPrestamos()

​aprobar()

​rechazar()

​Complete Usage Examples

​User Component (Request and View Loans)

​Admin Component (Manage All Loans)

​Data Model

​Prestamo Interface

​Estado (Status) Values

​Error Handling

​Authorization Requirements

​See Also

Overview

Constructor

Properties

Methods

solicitar()

getAll()

getMisPrestamos()

aprobar()

rechazar()

Complete Usage Examples

User Component (Request and View Loans)

Admin Component (Manage All Loans)

Data Model

Prestamo Interface

Estado (Status) Values

Error Handling

Authorization Requirements

See Also