added fromString method, improved code

.travis.yml

@@ -1,9 +1,9 @@
 language: php
 
 php:
-  - 7.3
-  - 7.4
   - 8.0
+  - 8.1
+  - 8.2
 
 sudo: false
 

LICENSE.md

@@ -1,6 +1,6 @@
 # The MIT License (MIT)
 
-Copyright (c) 2020 Burak Özdemir
+Copyright (c) 2023 Burak Özdemir
 
 > Permission is hereby granted, free of charge, to any person obtaining a copy
 > of this software and associated documentation files (the "Software"), to deal

README.md

@@ -33,6 +33,12 @@ $json->convertAndSave(__DIR__ . '/above.csv');
 $json->convertAndDownload();
 ```
 
+You can also convert directly from a JSON string using the `fromString` method.
+
+``` php
+$csvString = (new Json())->fromString('{"name": "Buddha", "age": 80}')->convert();
+```
+
 Assume that the input JSON is something like below. 
 
 ```json
@@ -82,6 +88,12 @@ $csv->convertAndSave(__DIR__ . '/below.json');
 $csv->convertAndDownload();
 ```
 
+You can also convert directly from a CSV string using the `fromString` method.
+
+``` php
+$jsonString = (new Csv())->fromString('[{"name":"Buddha","age":"80"}]')->convert();
+```
+
 Assume that the input CSV file is something like below. 
 
 **SepalLength**|**SepalWidth**|**PetalLength**|**PetalWidth**|**Name**

src/AbstractFile.php

@@ -7,49 +7,85 @@ abstract class AbstractFile
     /**
      * @var array
      */
-    protected $conversion;
+    protected $conversion = [];
 
     /**
      * @var string
      */
-    protected $data;
+    protected $data = '';
 
     /**
      * @var string
      */
-    protected $filename;
+    protected $filename = '';
 
     /**
-     * CsvToJson constructor.
+     * AbstractFile constructor.
+     *
+     * @param string|null $filepath
+     */
+    public function __construct(?string $filepath = null)
+    {
+        if ($filepath !== null) {
+            $this->loadFile($filepath);
+        }
+    }
+
+    /**
+     * Load data from a file.
      *
      * @param string $filepath
      */
-    public function __construct($filepath)
+    protected function loadFile(string $filepath): void
     {
+        if (!is_readable($filepath)) {
+            throw new \RuntimeException("File not readable: $filepath");
+        }
         [$this->filename, $this->data] = [pathinfo($filepath, PATHINFO_FILENAME), file_get_contents($filepath)];
     }
 
     /**
-     * @param null $filename
+     * @param string|null $filename
      * @param bool $exit
      */
-    public function convertAndDownload($filename = null, $exit = true)
+    public function convertAndDownload(?string $filename = null, bool $exit = true): void
     {
         $filename = $filename ?? $this->filename;
-        header('Content-disposition: attachment; filename=' . $filename . '.' . $this->conversion['extension']);
-        header('Content-type: ' . $this->conversion['type']);
+        $this->sendHeaders($filename);
         echo $this->convert();
         if ($exit === true) {
             exit();
         }
     }
 
+    /**
+     * Send headers for download.
+     *
+     * @param string $filename
+     */
+    protected function sendHeaders(string $filename): void
+    {
+        header('Content-disposition: attachment; filename=' . $filename . '.' . $this->conversion['extension']);
+        header('Content-type: ' . $this->conversion['type']);
+    }
+
+    /**
+     * @param string $dataString
+     *
+     * @return $this
+     */
+    public function fromString(string $dataString): AbstractFile
+    {
+        $this->data = $dataString;
+        return $this;
+    }
+
     /**
      * @param string $path
      *
      * @return bool|int
      */
-    public function convertAndSave($path): int
+    public function convertAndSave(string $path): int
     {
         return file_put_contents($path, $this->convert());
     }
@@ -71,12 +107,12 @@ public function getFilename(): string
     }
 
     /**
-     * @param string     $key
+     * @param string $key
      * @param string|int $value
      *
      * @return array
      */
-    public function setConversionKey($key, $value): array
+    public function setConversionKey(string $key, $value): array
     {
         $this->conversion[$key] = $value;
         return $this->conversion;

src/File/Csv.php

@@ -21,31 +21,59 @@ class Csv extends AbstractFile
     ];
 
     /**
-     * @return string
+     * Converts CSV data to JSON.
+     *
+     * @return string JSON representation of CSV data.
      */
     public function convert(): string
     {
         $data = $this->parseData();
         $keys = $this->parseCsv(array_shift($data));
-        $splitKeys = array_map(function ($key) {
+        $splitKeys = $this->splitKeys($keys);
+        $jsonObjects = array_map([$this, 'convertLineToJson'], $data, array_fill(0, count($data), $splitKeys));
+        $json = json_encode($jsonObjects, $this->conversion['options']);
+        if (json_last_error() !== JSON_ERROR_NONE) {
+            throw new \RuntimeException('JSON encoding failed: ' . json_last_error_msg());
+        }
+        return $json;
+    }
+
+    /**
+     * Splits keys based on the configured join delimiter.
+     *
+     * @param array $keys
+     * @return array
+     */
+    private function splitKeys(array $keys): array
+    {
+        return array_map(function ($key) {
             return explode($this->conversion['join'], $key);
         }, $keys);
-        return json_encode(array_map(function ($line) use ($splitKeys) {
-            return $this->getJsonObject($line, $splitKeys);
-        }, $data), $this->conversion['options']);
     }
 
     /**
-     * @param       $line
-     * @param       $splitKeys
-     * @param array $jsonObject
+     * Converts a CSV line to a JSON object.
      *
+     * @param string $line
+     * @param array $splitKeys
      * @return array
      */
-    private function getJsonObject($line, $splitKeys, array $jsonObject = []): array
+    private function convertLineToJson(string $line, array $splitKeys): array
     {
-        $values = $this->parseCsv($line);
-        for ($valueIndex = 0, $count = \count($values); $valueIndex < $count; $valueIndex++) {
+        return $this->getJsonObject($this->parseCsv($line), $splitKeys);
+    }
+
+    /**
+     * Creates a JSON object from a CSV line.
+     *
+     * @param array $values CSV values.
+     * @param array $splitKeys Split keys.
+     * @return array JSON object.
+     */
+    private function getJsonObject(array $values, array $splitKeys): array
+    {
+        $jsonObject = [];
+        for ($valueIndex = 0, $count = count($values); $valueIndex < $count; $valueIndex++) {
             if ($values[$valueIndex] === '') {
                 continue;
             }
@@ -55,19 +83,21 @@ private function getJsonObject($line, $splitKeys, array $jsonObject = []): array
     }
 
     /**
-     * @param $splitKey
-     * @param $splitKeyIndex
-     * @param $jsonObject
-     * @param $value
+     * Sets a value in a JSON object.
+     *
+     * @param array $splitKey Split key.
+     * @param int   $splitKeyIndex Split key index.
+     * @param array $jsonObject JSON object.
+     * @param mixed $value Value.
      */
-    private function setJsonValue($splitKey, $splitKeyIndex, &$jsonObject, $value): void
+    private function setJsonValue(array $splitKey, int $splitKeyIndex, array &$jsonObject, $value): void
     {
         $keyPart = $splitKey[$splitKeyIndex];
-        if (\count($splitKey) > $splitKeyIndex + 1) {
+        if (count($splitKey) > $splitKeyIndex + 1) {
             if (!array_key_exists($keyPart, $jsonObject)) {
                 $jsonObject[$keyPart] = [];
             }
-            $this->setJsonValue($splitKey, $splitKeyIndex+1, $jsonObject[$keyPart], $value);
+            $this->setJsonValue($splitKey, $splitKeyIndex + 1, $jsonObject[$keyPart], $value);
         } else {
             if (is_numeric($value) && $this->conversion['numbers'] === 'numbers') {
                 $value = 0 + $value;
@@ -77,11 +107,12 @@ private function setJsonValue($splitKey, $splitKeyIndex, &$jsonObject, $value):
     }
 
     /**
-     * @param $line
+     * Parses a CSV line.
      *
-     * @return array
+     * @param string $line CSV line.
+     * @return array Parsed CSV line.
      */
-    private function parseCsv($line): array
+    private function parseCsv(string $line): array
     {
         return str_getcsv(
             $line,
@@ -92,7 +123,9 @@ private function parseCsv($line): array
     }
 
     /**
-     * @return array
+     * Parses CSV data.
+     *
+     * @return array Parsed CSV data.
      */
     private function parseData(): array
     {