Complex classes like BaseResource 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 BaseResource, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 12 | abstract class BaseResource implements \Iterator  | 
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| 13 | { | 
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| 14 | |||
| 15 | /**  | 
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| 16 | * BaseResource constructor.  | 
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| 17 | *  | 
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| 18 | * @param object $descriptor  | 
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| 19 | * @param null|string $basePath  | 
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| 20 | *  | 
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| 21 | * @param bool $skipValidations  | 
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| 22 | *  | 
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| 23 | * @throws \frictionlessdata\datapackage\Exceptions\ResourceValidationFailedException  | 
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| 24 | */  | 
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| 25 | public function __construct($descriptor, $basePath, $skipValidations = false)  | 
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| 37 | |||
| 38 | public static function handlesDescriptor($descriptor)  | 
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| 42 | |||
| 43 | public function read($readOptions = null)  | 
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| 77 | |||
| 78 | /**  | 
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| 79 | * Loads $this->dataStreams based on $this->path() and $this->data  | 
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| 80 | * @return BaseDataStream[]|null  | 
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| 81 | */  | 
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| 82 | public function dataStreams()  | 
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| 97 | |||
| 98 | /**  | 
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| 99 | * @return object  | 
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| 100 | */  | 
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| 101 | public function descriptor()  | 
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| 105 | |||
| 106 | /**  | 
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| 107 | * @return string  | 
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| 108 | */  | 
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| 109 | public function name()  | 
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| 113 | |||
| 114 | public function path()  | 
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| 127 | |||
| 128 | /**  | 
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| 129 | * If the resource's $path is local (non-http)  | 
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| 130 | * @return bool  | 
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| 131 | */  | 
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| 132 | public function isLocal()  | 
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| 136 | |||
| 137 | /**  | 
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| 138 | * If the resource's $path is remote (http)  | 
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| 139 | * @return bool  | 
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| 140 | */  | 
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| 141 | public function isRemote()  | 
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| 146 | |||
| 147 | public function data()  | 
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| 151 | |||
| 152 | // standard iterator functions - to iterate over the data sources  | 
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| 153 | public function rewind()  | 
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| 161 | |||
| 162 | public function current()  | 
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| 166 | |||
| 167 | public function key()  | 
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| 171 | |||
| 172 | public function next()  | 
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| 176 | |||
| 177 | public function valid()  | 
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| 194 | |||
| 195 | public function getFileExtension()  | 
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| 199 | |||
| 200 | public function save($baseFilename)  | 
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| 219 | |||
| 220 | public static function validateDataSource($dataSource, $basePath = null)  | 
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| 233 | |||
| 234 | /**  | 
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| 235 | * allows extending classes to add custom sources  | 
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| 236 | * used by unit tests to add a mock http source.  | 
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| 237 | *  | 
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| 238 | * @param string $dataSource  | 
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| 239 | * @param string|null $basePath  | 
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| 240 | *  | 
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| 241 | * @return string  | 
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| 242 | */  | 
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| 243 | public static function normalizeDataSource($dataSource, string $basePath = null)  | 
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| 255 | |||
| 256 | protected $descriptor;  | 
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| 257 | protected $basePath;  | 
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| 258 | protected $skipValidations = false;  | 
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| 259 | protected $currentDataPosition = 0;  | 
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| 260 | protected $currentDataStream = 0;  | 
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| 261 | protected $dataStreams = null;  | 
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| 262 | |||
| 263 | protected function validateResource()  | 
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| 267 | |||
| 268 | /**  | 
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| 269 | * @param string $dataSource  | 
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| 270 | *  | 
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| 271 | * @return BaseDataStream  | 
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| 272 | */  | 
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| 273 | abstract protected function getDataStream($dataSource);  | 
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| 274 | |||
| 275 | abstract protected function getInlineDataStream($data);  | 
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| 276 | |||
| 277 | protected static function handlesProfile($profile)  | 
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| 281 | }  | 
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| 282 | 
There are different options of fixing this problem.
If you want to be on the safe side, you can add an additional type-check:
If you are sure that the expression is traversable, you might want to add a doc comment cast to improve IDE auto-completion and static analysis:
Mark the issue as a false-positive: Just hover the remove button, in the top-right corner of this issue for more options.