拥有一个Eloquent模型，是否可以在运行时获取其所有关系及其类型？
我试着看了ReflectionClass，但找不到任何对这个场景有用的东西。
例如，如果我们有经典的Post模型，有没有一种方法可以提取这样的关系？
- belongsTo: User
- belongsToMany: Tag
要做到这一点，您必须知道模型中方法的名称，它们可能会有很大的变化；）
想法：
-
如果你在方法中得到了一个模式，比如relUser/relTag，你可以过滤掉
-
或者循环所有公共方法，看看是否弹出
Relation对象（坏主意） -
您可以定义一个
protected $relationMethods（注意：Laravel已经使用了$relations），它包含一个带有方法的数组。
调用Post->User（）后，您将收到一个BelongsTo或一个来自Relation族的其他对象，因此您可以列出关系类型。
[编辑：评论后]
如果模型配备了受保护的$with = array(...);，则在加载记录后，您可以查看与$Model->getRelations()的加载关系。当没有加载记录时，这是不可能的，因为关系还没有被触及。
getRelations()在/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php 中
但目前它没有出现在laravel.com/api的api中，这是因为我们有更新的版本
就像Rob说的那样。循环遍历每个公共方法并检查是否返回了关系是个坏主意。
Barryvdh在他非常受欢迎的Laravel-ide助手中使用了基于Regex的方法：https://github.com/barryvdh/laravel-ide-helper/blob/master/src/Console/ModelsCommand.php
您只需要在调用getPropertiesFromMethods后过滤您接收到的属性，如下所示（未经测试的示例）：
class classSniffer{
private $properties = [];
//...
public function getPropertiesFromMethods($model){
//the copied code from the class above (ModelsCommand@getPropertiesFromMethods)
}
public function getRelationsFrom($model){
$this->getPropertiesFromMethods($model);
$relations = [];
foreach($this->properties as $name => $property){
$type = $property;
$isRelation = strstr($property[$type], 'Illuminate'Database'Eloquent'Relations');
if($isRelation){
$relations[$name] = $property;
}
}
return $relations;
}
}
有没有一种更清洁的方法可以做到这一点而不接触模型？
我认为我们必须等待PHP7（返回类型反射）或Taylor ^^的新反射服务
我最近一直在做同样的事情，我认为没有反射就无法有效地完成。但这有点资源密集型，所以我应用了一些缓存。需要进行的一项检查是验证返回类型和php7之前的版本，这只能通过实际执行每个方法来完成。因此，在进行检查之前，我还应用了一些逻辑来减少可能的候选人数量。
/**
* Identify all relationships for a given model
*
* @param object $model Model
* @param string $heritage A flag that indicates whether parent and/or child relationships should be included
* @return array
*/
public function getAllRelations('Illuminate'Database'Eloquent'Model $model = null, $heritage = 'all')
{
$model = $model ?: $this;
$modelName = get_class($model);
$types = ['children' => 'Has', 'parents' => 'Belongs', 'all' => ''];
$heritage = in_array($heritage, array_keys($types)) ? $heritage : 'all';
if ('Illuminate'Support'Facades'Cache::has($modelName."_{$heritage}_relations")) {
return 'Illuminate'Support'Facades'Cache::get($modelName."_{$heritage}_relations");
}
$reflectionClass = new 'ReflectionClass($model);
$traits = $reflectionClass->getTraits(); // Use this to omit trait methods
$traitMethodNames = [];
foreach ($traits as $name => $trait) {
$traitMethods = $trait->getMethods();
foreach ($traitMethods as $traitMethod) {
$traitMethodNames[] = $traitMethod->getName();
}
}
// Checking the return value actually requires executing the method. So use this to avoid infinite recursion.
$currentMethod = collect(explode('::', __METHOD__))->last();
$filter = $types[$heritage];
$methods = $reflectionClass->getMethods('ReflectionMethod::IS_PUBLIC); // The method must be public
$methods = collect($methods)->filter(function ($method) use ($modelName, $traitMethodNames, $currentMethod) {
$methodName = $method->getName();
if (!in_array($methodName, $traitMethodNames) //The method must not originate in a trait
&& strpos($methodName, '__') !== 0 //It must not be a magic method
&& $method->class === $modelName //It must be in the self scope and not inherited
&& !$method->isStatic() //It must be in the this scope and not static
&& $methodName != $currentMethod //It must not be an override of this one
) {
$parameters = (new 'ReflectionMethod($modelName, $methodName))->getParameters();
return collect($parameters)->filter(function ($parameter) {
return !$parameter->isOptional(); // The method must have no required parameters
})->isEmpty(); // If required parameters exist, this will be false and omit this method
}
return false;
})->mapWithKeys(function ($method) use ($model, $filter) {
$methodName = $method->getName();
$relation = $model->$methodName(); //Must return a Relation child. This is why we only want to do this once
if (is_subclass_of($relation, 'Illuminate'Database'Eloquent'Relations'Relation::class)) {
$type = (new 'ReflectionClass($relation))->getShortName(); //If relation is of the desired heritage
if (!$filter || strpos($type, $filter) === 0) {
return [$methodName => get_class($relation->getRelated())]; // ['relationName'=>'relatedModelClass']
}
}
return false; // Remove elements reflecting methods that do not have the desired return type
})->toArray();
'Illuminate'Support'Facades'Cache::forever($modelName."_{$heritage}_relations", $methods);
return $methods;
}
我知道这有点晚了，但我已经多次访问这个问题，所以我想分享我的观察结果，以帮助那些将来访问这个问题的人。
这是我用来从一个雄辩的模型类中提取关系的方法。
/**
*
* Returns all the relationship methods defined
* in the provided model class with related
* model class and relation function name
*
* @param string $modelClass exampe: App'Models'Post
* @return array $relattions array containing information about relationships
*/
protected function getModelRelationshipMethods(string $modelClass)
{
//can define this at class level
$relationshipMethods = [
'hasMany',
'hasOne',
'belongsTo',
'belongsToMany',
];
$reflector = new ReflectionClass($modelClass);
$path = $reflector->getFileName();
//lines of the file
$lines = file($path);
$methods = $reflector->getMethods();
$relations = [];
foreach ($methods as $method) {
//if its a concrete class method
if ($method->class == $modelClass) {
$start = $method->getStartLine();
$end = $method->getEndLine();
//loop through lines of the method
for($i = $start-1; $i<=$end-1; $i++) {
// look for text between -> and ( assuming that its on one line
preg_match('~'->(.*?)'(~', $lines[$i], $matches);
// if there is a match
if (count($matches)) {
//loop to check if the found text is in relationshipMethods list
foreach ($matches as $match) {
// if so add it to the output array
if (in_array($match, $relationshipMethods)) {
$relations[] = [
//function name of the relation definition
'method_name' => $method->name,
//type of relation
'relation' => $match,
//related Class name
'related' => (preg_match('/'.$match.''((.*?),/', $lines[$i], $related) == 1) ? $related[1] : null,
];
}
}
}
}
}
}
return $relations;
}
如果您对App/Post模型返回的$relationships进行dd（）或dump（），则输出将类似于以下
^ array:3 [
0 => array:3 [
"method_name" => "user"
"relation" => "belongsTo"
"related" => "User::class"
]
1 => array:3 [
"method_name" => "tag"
"relation" => "belongsToMany"
"related" => "Tag::class"
]
2 => array:3 [
"method_name" => "comments"
"relation" => "hasMany"
"related" => "Comment::class"
]
]
我的项目也有同样的需求。我的解决方案是使用get_class函数来检查关系的类型。示例：
$invoice = App'Models'Invoice::with('customer', 'products', 'invoiceProducts', 'invoiceProduct')->latest()->first();
foreach ($invoice->getRelations() as $relation => $items) {
$model = get_class($invoice->{$relation}());
$type = explode('''', $model);
$type = $type[count($type) - 1];
$relations[] = ['name' => $relation, 'type' => $type];
}
dd($relations);
示例结果：
array:4 [▼
0 => array:2 [▼
"name" => "customer"
"type" => "BelongsTo"
]
1 => array:2 [▼
"name" => "products"
"type" => "BelongsToMany"
]
2 => array:2 [▼
"name" => "invoiceProducts"
"type" => "HasMany"
]
3 => array:2 [▼
"name" => "invoiceProduct"
"type" => "HasOne"
]
]
我需要它来复制一个模型项，包括关系
composer require adideas/laravel-get-relationship-eloquent-model
https://packagist.org/packages/adideas/laravel-get-relationship-eloquent-model
拉拉威尔得到关系所有雄辩的模型！
这样做不需要知道模型中方法的名称。有了这个包，您可以在运行时获得一个或多个Eloquent模型的所有关系及其类型