B. Carpeta « lib / php »

Versión para imprimir.

1. lib / php / ejecutaServicio.php

1<?php
2
3require_once __DIR__ . "/JsonResponse.php";
4require_once __DIR__ . "/ProblemDetails.php";
5
6/**
7 * Ejecuta una funcion que implementa un servicio.
8 */
9function ejecutaServicio($servicio)
10{
11 try {
12 $resultado = $servicio();
13 if (!($resultado instanceof JsonResponse)) {
14 $resultado = JsonResponse::ok($resultado);
15 }
16 procesa_json_response($resultado);
17 } catch (ProblemDetails $details) {
18 procesa_problem_details($details);
19 } catch (Throwable $throwable) {
20 procesa_problem_details(new ProblemDetails(
21 status: ProblemDetails::InternalServerError,
22 type: "/error/errorinterno.html",
23 title: "Error interno del servidor.",
24 detail: $throwable->getMessage()
25 ));
26 }
27}
28
29function procesa_json_response(JsonResponse $response)
30{
31 $json = "";
32 $body = $response->body;
33 if ($response->status !== JsonResponse_NoContent) {
34 $json = json_encode($body);
35 if ($json === false) {
36 no_puede_generar_json();
37 return;
38 }
39 }
40 http_response_code($response->status);
41 if ($response->location !== null) {
42 header("Location: {$response->location}");
43 }
44 if ($response->status !== JsonResponse_NoContent) {
45 header("Content-Type: application/json");
46 echo $json;
47 }
48}
49
50function procesa_problem_details(ProblemDetails $details)
51{
52 $body = ["title" => $details->title];
53 if ($details->type !== null) {
54 $body["type"] = $details->type;
55 }
56 if ($details->detail !== null) {
57 $body["detail"] = $details->detail;
58 }
59 $json = json_encode($body);
60 if ($json === false) {
61 no_puede_generar_json();
62 } else {
63 http_response_code($details->status);
64 header("Content-Type: application/problem+json");
65 echo $json;
66 }
67}
68
69function no_puede_generar_json()
70{
71 http_response_code(ProblemDetails::InternalServerError);
72 header("Content-Type: application/problem+json");
73 echo '{"type":"/error/nojson.html"'
74 . ',"title":"El valor devuelto no puede representarse como JSON."}';
75}
76

2. lib / php / JsonResponse.php

1<?php
2
3const JsonResponse_OK = 200;
4const JsonResponse_Created = 201;
5const JsonResponse_NoContent = 204;
6
7class JsonResponse
8{
9
10 public int $status;
11 public $body;
12 public ?string $location;
13
14 public function __construct(
15 int $status = JsonResponse_OK,
16 $body = null,
17 ?string $location = null
18 ) {
19 $this->status = $status;
20 $this->body = $body;
21 $this->location = $location;
22 }
23
24 public static function ok($body)
25 {
26 return new JsonResponse(body: $body);
27 }
28
29 public static function created(string $location, $body)
30 {
31 return new JsonResponse(JsonResponse_Created, $body, $location);
32 }
33
34 public static function noContent()
35 {
36 return new JsonResponse(JsonResponse_NoContent, null);
37 }
38}
39

3. lib / php / leeTexto.php

1<?php
2
3/**
4 * Recupera el texto de un parámetro enviado al
5 * servidor por medio de GET, POST o cookie.
6 * Si el parámetro no se recibe, devuelve null.
7 */
8function leeTexto(string $parametro): ?string
9{
10 /* Si el parámetro está asignado en $_REQUEST,
11 * devuelve su valor; de lo contrario,
12 * devuelve null. */
13 $valor = isset($_REQUEST[$parametro])
14 ? $_REQUEST[$parametro]
15 : null;
16 return $valor;
17}
18

4. lib / php / ProblemDetails.php

1<?php
2
3class ProblemDetails extends Exception
4{
5
6 public const BadRequest = 400;
7 public const NotFound = 404;
8 public const InternalServerError = 500;
9
10 public int $status;
11 public string $title;
12 public ?string $type;
13 public ?string $detail;
14
15 public function __construct(
16 int $status,
17 string $title,
18 ?string $type = null,
19 ?string $detail = null,
20 Throwable $previous = null
21 ) {
22 parent::__construct($title, $status, $previous);
23 $this->status = $status;
24 $this->type = $type;
25 $this->title = $title;
26 $this->detail = $detail;
27 }
28}
29

5. lib / php / recibeFetchAll.php

1<?php
2
3function recibeFetchAll(false|array $resultado): array
4{
5 if ($resultado === false) {
6 return [];
7 } else {
8 return $resultado;
9 }
10}
11