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| 1 | +<?php |
| 2 | + |
| 3 | +declare(strict_types=1); |
| 4 | + |
| 5 | +/** |
| 6 | + * This file is part of CodeIgniter 4 framework. |
| 7 | + * |
| 8 | + * (c) CodeIgniter Foundation <[email protected]> |
| 9 | + * |
| 10 | + * For the full copyright and license information, please view |
| 11 | + * the LICENSE file that was distributed with this source code. |
| 12 | + */ |
| 13 | + |
| 14 | +namespace CodeIgniter\API; |
| 15 | + |
| 16 | +use CodeIgniter\Entity\Entity; |
| 17 | +use CodeIgniter\HTTP\IncomingRequest; |
| 18 | +use InvalidArgumentException; |
| 19 | + |
| 20 | +/** |
| 21 | + * Base class for transforming resources into arrays. |
| 22 | + * Fulfills common functionality of the TransformerInterface, |
| 23 | + * and provides helper methods for conditional inclusion/exclusion of values. |
| 24 | + * |
| 25 | + * Supports the following query variables from the request: |
| 26 | + * - fields: Comma-separated list of fields to include in the response |
| 27 | + * (e.g., ?fields=id,name,email) |
| 28 | + * If not provided, all fields from toArray() are included. |
| 29 | + * - include: Comma-separated list of related resources to include |
| 30 | + * (e.g., ?include=posts,comments) |
| 31 | + * This looks for methods named `include{Resource}()` on the transformer, |
| 32 | + * and calls them to get the related data, which are added as a new key to the output. |
| 33 | + * |
| 34 | + * Example: |
| 35 | + * |
| 36 | + * class UserTransformer extends BaseTransformer |
| 37 | + * { |
| 38 | + * public function toArray(mixed $resource): array |
| 39 | + * { |
| 40 | + * return [ |
| 41 | + * 'id' => $resource['id'], |
| 42 | + * 'name' => $resource['name'], |
| 43 | + * 'email' => $resource['email'], |
| 44 | + * 'created_at' => $resource['created_at'], |
| 45 | + * 'updated_at' => $resource['updated_at'], |
| 46 | + * 'bio' => $this->when(($resource['bio'] ?? null) !== null, $resource['bio'] ?? null), |
| 47 | + * ]; |
| 48 | + * } |
| 49 | + * |
| 50 | + * protected function includePosts(): array |
| 51 | + * { |
| 52 | + * $posts = model('PostModel')->where('user_id', $this->resource['id'])->findAll(); |
| 53 | + * return (new PostTransformer())->transformMany($posts); |
| 54 | + * } |
| 55 | + * } |
| 56 | + */ |
| 57 | +abstract class BaseTransformer implements TransformerInterface |
| 58 | +{ |
| 59 | + private ?array $fields = null; |
| 60 | + private ?array $includes = null; |
| 61 | + protected mixed $resource = null; |
| 62 | + |
| 63 | + public function __construct( |
| 64 | + private ?IncomingRequest $request = null, |
| 65 | + ) |
| 66 | + { |
| 67 | + $this->request = $request ?? request(); |
| 68 | + |
| 69 | + $fields = $this->request->getGet('fields'); |
| 70 | + $this->fields = is_string($fields) |
| 71 | + ? array_map('trim', explode(',', $fields)) |
| 72 | + : $fields; |
| 73 | + |
| 74 | + $includes = $this->request->getGet('include'); |
| 75 | + $this->includes = is_string($includes) |
| 76 | + ? array_map('trim', explode(',', $includes)) |
| 77 | + : $includes; |
| 78 | + } |
| 79 | + |
| 80 | + /** |
| 81 | + * Converts the resource to an array representation. |
| 82 | + * This is overridden by child classes to define the |
| 83 | + * API-safe resource representation. |
| 84 | + * |
| 85 | + * @param mixed $resource The resource being transformed |
| 86 | + */ |
| 87 | + abstract public function toArray(mixed $resource): array; |
| 88 | + |
| 89 | + /** |
| 90 | + * Transforms the given resource into an array using |
| 91 | + * the $this->toArray(). |
| 92 | + */ |
| 93 | + public function transform(mixed $resource = null): array |
| 94 | + { |
| 95 | + // Store the resource so include methods can access it |
| 96 | + $this->resource = $resource; |
| 97 | + |
| 98 | + if ($resource === null) { |
| 99 | + $data = $this->toArray(null); |
| 100 | + } else { |
| 101 | + $data = $resource instanceof Entity |
| 102 | + ? $this->toArray($resource->toArray()) |
| 103 | + : $this->toArray((array) $resource); |
| 104 | + } |
| 105 | + |
| 106 | + $data = $this->limitFields($data); |
| 107 | + |
| 108 | + return $this->insertIncludes($data); |
| 109 | + } |
| 110 | + |
| 111 | + /** |
| 112 | + * Transforms a collection of resources using $this->transform() on each item. |
| 113 | + * |
| 114 | + * If the request's 'fields' query variable is set, only those fields will be included |
| 115 | + * in the transformed output. |
| 116 | + */ |
| 117 | + public function transformMany(array $resources): array |
| 118 | + { |
| 119 | + return array_map(fn($resource) => $this->transform($resource), $resources); |
| 120 | + } |
| 121 | + |
| 122 | + /** |
| 123 | + * Conditionally include a value. |
| 124 | + * |
| 125 | + * @param mixed $value |
| 126 | + * @param mixed $default |
| 127 | + * @return mixed |
| 128 | + */ |
| 129 | + protected function when(bool $condition, $value, $default = null) |
| 130 | + { |
| 131 | + return $condition ? $value : $default; |
| 132 | + } |
| 133 | + |
| 134 | + /** |
| 135 | + * Conditionally exclude a value. |
| 136 | + */ |
| 137 | + protected function whenNot(bool $condition, $value, $default = null) |
| 138 | + { |
| 139 | + return ! $condition ? $value : $default; |
| 140 | + } |
| 141 | + |
| 142 | + /** |
| 143 | + * Define which fields can be requested via the 'fields' query parameter. |
| 144 | + * Override in child classes to restrict available fields. |
| 145 | + * Return null to allow all fields from toArray(). |
| 146 | + */ |
| 147 | + protected function getAllowedFields(): ?array |
| 148 | + { |
| 149 | + return null; |
| 150 | + } |
| 151 | + |
| 152 | + /** |
| 153 | + * Define which related resources can be included via the 'include' query parameter. |
| 154 | + * Override in child classes to restrict available includes. |
| 155 | + * Return null to allow all includes that have corresponding methods. |
| 156 | + * Return an empty array to disable all includes. |
| 157 | + */ |
| 158 | + protected function getAllowedIncludes(): ?array |
| 159 | + { |
| 160 | + return null; |
| 161 | + } |
| 162 | + |
| 163 | + /** |
| 164 | + * Limits the given data array to only the fields specified |
| 165 | + * |
| 166 | + * @throws InvalidArgumentException |
| 167 | + */ |
| 168 | + private function limitFields(array $data): array |
| 169 | + { |
| 170 | + if ($this->fields === null || $this->fields === []) { |
| 171 | + return $data; |
| 172 | + } |
| 173 | + |
| 174 | + $allowedFields = $this->getAllowedFields(); |
| 175 | + |
| 176 | + // If whitelist is defined, validate against it |
| 177 | + if ($allowedFields !== null) { |
| 178 | + $invalidFields = array_diff($this->fields, $allowedFields); |
| 179 | + |
| 180 | + if ($invalidFields !== []) { |
| 181 | + throw ApiException::forInvalidFields(implode(', ', $invalidFields)); |
| 182 | + } |
| 183 | + } |
| 184 | + |
| 185 | + return array_intersect_key($data, array_flip($this->fields)); |
| 186 | + } |
| 187 | + |
| 188 | + /** |
| 189 | + * Checks the request for 'include' query variable, and if present, |
| 190 | + * calls the corresponding include{Resource} methods to add related data. |
| 191 | + */ |
| 192 | + private function insertIncludes(array $data): array |
| 193 | + { |
| 194 | + if ($this->includes === null) { |
| 195 | + return $data; |
| 196 | + } |
| 197 | + |
| 198 | + $allowedIncludes = $this->getAllowedIncludes(); |
| 199 | + |
| 200 | + if ($allowedIncludes === []) { |
| 201 | + return $data; // No includes allowed |
| 202 | + } |
| 203 | + |
| 204 | + // If whitelist is defined, filter the requested includes |
| 205 | + if ($allowedIncludes !== null) { |
| 206 | + $invalidIncludes = array_diff($this->includes, $allowedIncludes); |
| 207 | + |
| 208 | + if ($invalidIncludes !== []) { |
| 209 | + throw ApiException::forInvalidIncludes(implode(', ', $invalidIncludes)); |
| 210 | + } |
| 211 | + } |
| 212 | + |
| 213 | + foreach ($this->includes as $include) { |
| 214 | + $method = 'include' . ucfirst($include); |
| 215 | + if (method_exists($this, $method)) { |
| 216 | + $data[$include] = $this->$method(); |
| 217 | + } else { |
| 218 | + throw ApiException::forMissingInclude($include); |
| 219 | + } |
| 220 | + } |
| 221 | + |
| 222 | + return $data; |
| 223 | + } |
| 224 | +} |
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