Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Dispatcher often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Dispatcher, and based on these observations, apply Extract Interface, too.
1 | <?php |
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26 | class Dispatcher |
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27 | { |
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28 | /** |
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29 | * Dispatcher default options. |
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30 | * |
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31 | * @var array |
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32 | */ |
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33 | protected static $defaults = [ |
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34 | 'stringHandlerPattern' => '::', |
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35 | 'autoWire' => true |
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36 | ]; |
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37 | /** |
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38 | * @var array |
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39 | */ |
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40 | private $options; |
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41 | /** |
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42 | * @var array |
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43 | */ |
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44 | private $providedArguments; |
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45 | /** |
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46 | * @var array |
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47 | */ |
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48 | private $constructParams; |
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49 | |||
50 | /** |
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51 | * Handler Class Namespaces. |
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52 | * |
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53 | * @var array. |
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54 | */ |
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55 | private $namespaces = []; |
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56 | |||
57 | /** |
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58 | * Dispatcher constructor. |
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59 | * |
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60 | * @param array $options |
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61 | */ |
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62 | 2 | public function __construct(array $options = array()) |
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67 | |||
68 | /** |
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69 | * Get response from handler string. |
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70 | * |
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71 | * @param $request |
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72 | * @param string|\Closure $handler |
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73 | * @param array $constructor |
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74 | * @return ResponseInterface |
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75 | * @throws \Exception |
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76 | */ |
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77 | public function dispatch(ServerRequestInterface $request, $handler, array $constructor = array()) |
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78 | { |
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79 | $handlerType = \gettype($handler); |
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80 | $response = null; |
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81 | |||
82 | switch ($handlerType) { |
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83 | case 'string': |
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84 | |||
85 | $params = \explode($this->options['stringHandlerPattern'], $handler); |
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86 | if (!isset($params[1])){ |
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87 | $response = $handler; |
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88 | break; |
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89 | } |
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90 | |||
91 | $resolvedHandler = $this->_processStringHandler($handler); |
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92 | $this->_getParams($resolvedHandler['controller'], $constructor); |
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93 | $response = $this->_callController($request, $resolvedHandler['controller'], $resolvedHandler['method']); |
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94 | break; |
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95 | case 'object': |
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96 | if (\is_callable($handler)) { |
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97 | $response = $handler($request); |
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98 | } |
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99 | break; |
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100 | default: |
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101 | throw new DispatchException( |
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102 | "Handler type: {$handlerType} is not valid." |
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103 | ); |
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104 | } |
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105 | |||
106 | if (!$response instanceof ResponseInterface) { |
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107 | $response = $this->createNewResponse($response); |
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108 | } |
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109 | return $response; |
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110 | } |
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111 | |||
112 | /*** |
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113 | * Get Controller/Method from handler string. |
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114 | * |
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115 | * @param $handler |
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116 | * @return mixed |
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117 | * @throws DispatchException |
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118 | */ |
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119 | protected function _processStringHandler($handler) |
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120 | { |
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121 | $controllerMethod = \explode( |
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122 | $this->options['stringHandlerPattern'], $handler |
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123 | ); |
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124 | |||
125 | try { |
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126 | $resolvedHandler['controller'] = $this->_findClass($controllerMethod[0]); |
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127 | } catch (\Exception $e) { |
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128 | throw new DispatchException($e->getMessage()); |
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129 | } |
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130 | |||
131 | $resolvedHandler['method'] = $controllerMethod[1] ?? null; |
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132 | |||
133 | return $resolvedHandler; |
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134 | } |
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135 | |||
136 | /** |
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137 | * Find class from namespace. |
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138 | * |
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139 | * @param string $class |
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140 | * @return string |
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141 | * @throws DispatchException |
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142 | */ |
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143 | protected function _findClass($class) |
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144 | { |
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145 | if (\class_exists($class)) { |
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146 | return $class; |
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147 | } |
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148 | |||
149 | foreach ($this->namespaces as $namespace) { |
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150 | if (\class_exists($namespace . $class)) { |
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151 | return $namespace . $class; |
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152 | } |
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153 | } |
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154 | |||
155 | throw new DispatchException("Controller : {$class} does not exist"); |
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156 | } |
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157 | |||
158 | /** |
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159 | * Find class construct parameters from provided arguments. |
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160 | * |
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161 | * @param string $controllerName |
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162 | * @param array $args |
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163 | * @return array |
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164 | * @throws DispatchException |
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165 | */ |
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166 | protected function _getParams(string $controllerName, array $args) |
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167 | { |
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168 | if ($this->options['autoWire'] === false) { |
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169 | $this->providedArguments = $args; |
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170 | return $this->providedArguments; |
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171 | } |
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172 | |||
173 | $this->providedArguments = []; |
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174 | $this->constructParams = $this->_getConstructParams($controllerName); |
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175 | |||
176 | try { |
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177 | $this->_getParamsFromVariableName($args); |
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178 | } catch (\Exception $e) { |
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179 | $this->_getParamsFromTypeHint($args); |
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180 | } |
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181 | |||
182 | View Code Duplication | if (\count($this->providedArguments) - \count($this->constructParams) > 0) { |
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183 | throw new DispatchException('Missing parameters'); |
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184 | } |
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185 | |||
186 | \ksort($this->providedArguments); |
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187 | return $this->providedArguments; |
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188 | } |
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189 | |||
190 | /** |
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191 | * Reflect Controller construct and get parameters. |
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192 | * |
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193 | * @param $controllerName |
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194 | * @internal |
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195 | * |
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196 | * @return \ReflectionParameter[] |
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197 | */ |
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198 | protected function _getConstructParams($controllerName) |
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199 | { |
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200 | $controllerReflection = new \ReflectionClass($controllerName); |
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201 | $constructor = $controllerReflection->getConstructor(); |
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202 | |||
203 | if (null === $constructor) { |
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204 | return []; |
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205 | } |
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206 | |||
207 | return $constructor->getParameters(); |
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208 | } |
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209 | |||
210 | /** |
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211 | * Find controller constructor params based on $arg[index] |
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212 | * |
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213 | * @param $args |
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214 | * @throws DispatchException |
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215 | */ |
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216 | protected function _getParamsFromVariableName($args) |
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217 | { |
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218 | foreach ($this->constructParams as $index => $param) { |
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219 | $parameterVarName = $param->getName(); |
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220 | $constructorParamIndex = (int)$param->getPosition(); |
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221 | |||
222 | if (isset($args[$parameterVarName])) { |
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223 | $this->providedArguments[$constructorParamIndex] = $args[$parameterVarName]; |
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224 | } |
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225 | } |
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226 | View Code Duplication | if (\count($this->constructParams) - \count($this->providedArguments) > 0) { |
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227 | throw new DispatchException('Missing parameters'); |
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228 | } |
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229 | } |
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230 | |||
231 | /** |
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232 | * Find missing parameters based on Class name or type hint. |
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233 | * |
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234 | * @param $args |
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235 | */ |
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236 | protected function _getParamsFromTypeHint($args) |
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237 | { |
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238 | $processedArgs = $this->_processConstructArgs($args); |
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239 | |||
240 | foreach ($this->constructParams as $index => $param) { |
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241 | |||
242 | /** |
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243 | * @var \ReflectionClass $constructorParamClass ; |
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244 | */ |
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245 | $constructorParamClass = $param->getClass(); |
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246 | $constructorParamIndex = (int)$param->getPosition(); |
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247 | |||
248 | if (isset($this->providedArguments[$constructorParamIndex])) { |
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249 | continue; |
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250 | } |
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251 | |||
252 | if ($constructorParamClass) { |
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253 | $constructParamTypeHint = $constructorParamClass->getName(); |
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254 | foreach ((array)$processedArgs['object'] as $useParam) { |
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255 | $key = \array_search($constructParamTypeHint, $useParam['interfaces'], true); |
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256 | if ($key !== false) { |
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257 | $this->providedArguments[$constructorParamIndex] = $useParam['value']; |
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258 | } |
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259 | } |
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260 | } |
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261 | } |
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262 | } |
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263 | |||
264 | /** |
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265 | * Process provided arguments. |
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266 | * |
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267 | * @param array $args |
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268 | * @return array |
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269 | */ |
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270 | protected function _processConstructArgs(array $args = []) |
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271 | { |
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272 | $arguments = []; |
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273 | foreach ($args as $index => $param) { |
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274 | switch (\gettype($param)) { |
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275 | case 'object': |
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276 | $arguments['object'][] = [ |
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277 | 'class' => \get_class($param), |
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278 | 'interfaces' => \class_implements($param), |
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279 | 'value' => $param |
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280 | ]; |
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281 | break; |
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282 | } |
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283 | } |
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284 | return $arguments; |
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285 | } |
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286 | |||
287 | /** |
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288 | * Call controller with provided request and return Response. |
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289 | * |
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290 | * @param ServerRequestInterface $request Server Request |
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291 | * @param string $controller Controller class. |
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292 | * @param string $method Controller method. |
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293 | * |
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294 | * @return ResponseInterface |
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295 | * @throws DispatchException |
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296 | */ |
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297 | protected function _callController(ServerRequestInterface $request, string $controller, string $method) |
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298 | { |
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299 | |||
300 | if (!class_exists($controller)){ |
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301 | throw new DispatchException('Unable to locate controller: '.$controller); |
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302 | } |
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303 | |||
304 | $controllerObj = new $controller(...$this->providedArguments); |
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305 | |||
306 | try { |
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307 | $this->_checkWhiteList($controller, $this->options); |
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308 | $this->_checkBlackList($controller, $this->options); |
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309 | } catch (\Exception $e) { |
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310 | unset($controllerObj); |
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311 | throw new DispatchException($e->getMessage()); |
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312 | } |
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313 | |||
314 | if (!method_exists($controllerObj,$method)){ |
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315 | throw new DispatchException('Unable to locate method: '.$controller.'::'.$method); |
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316 | } |
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317 | |||
318 | return $controllerObj->{$method}($request); |
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319 | } |
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320 | |||
321 | /** |
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322 | * Checks controller instance against whitelist. |
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323 | * |
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324 | * @param $controller |
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325 | * @param $options |
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326 | * @throws DispatchException |
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327 | */ |
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328 | View Code Duplication | protected function _checkWhiteList($controller, $options) |
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329 | { |
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330 | if (isset($options['blacklist'])) { |
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331 | if (!$this->_checkInList($controller, $options['blacklist'])) { |
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332 | throw new DispatchException("Controller: {$controller}, not part of allowed whitelist."); |
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333 | } |
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334 | } |
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335 | } |
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336 | |||
337 | /** |
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338 | * Internal function for checking controller instance against class list. |
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339 | * |
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340 | * @param $controller |
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341 | * @param array $classList |
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342 | * @internal |
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343 | * @return bool |
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344 | */ |
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345 | protected function _checkInList($controller, array $classList) |
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346 | { |
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347 | foreach ((array)$classList as $classes) { |
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348 | if ($controller instanceof $classes) { |
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349 | return true; |
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350 | } |
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351 | } |
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352 | return false; |
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353 | } |
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354 | |||
355 | /** |
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356 | * Checks controller instance against blacklist. |
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357 | * |
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358 | * @param $controller |
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359 | * @param $options |
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360 | * @throws DispatchException |
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361 | */ |
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362 | View Code Duplication | protected function _checkBlackList($controller, $options) |
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363 | { |
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364 | if (isset($options['blacklist'])) { |
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365 | if ($this->_checkInList($controller, $options['blacklist'])) { |
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366 | throw new DispatchException("Controller: {$controller}, found on blacklist."); |
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367 | } |
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368 | } |
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369 | } |
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370 | |||
371 | /** |
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372 | * Create a new PSR-7 Response. |
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373 | * |
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374 | * @param $controllerResponse |
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375 | * @return Response |
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376 | * @throws \InvalidArgumentException |
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377 | */ |
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378 | public function createNewResponse($controllerResponse) |
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379 | { |
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380 | $response = new Response(); |
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381 | $body = new Stream("php://memory", "wb+"); |
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382 | $body->write($controllerResponse); |
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383 | $body->rewind(); |
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384 | return $response->withBody($body); |
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385 | } |
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386 | |||
387 | /** |
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388 | * With Class Namespace. |
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389 | * |
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390 | * @param $namespace |
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391 | * @return Dispatcher |
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392 | */ |
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393 | 1 | public function withNamespace($namespace) |
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399 | |||
400 | /** |
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401 | * With class Namespaces. |
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402 | * |
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403 | * @param array $namespaces |
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404 | * @return Dispatcher |
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405 | */ |
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406 | 1 | public function withNamespaces(array $namespaces) |
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407 | { |
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408 | 1 | $new = clone $this; |
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409 | 1 | foreach ($namespaces as $ns) { |
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410 | 1 | $new->namespaces[$ns] = $ns; |
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411 | } |
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412 | 1 | return $new; |
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414 | } |
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415 |
According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.
}
To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.