fix/improve HeaderUtil::normalize()

Author: codemasher

src/HeaderUtil.php

@@ -30,58 +30,49 @@ public static function normalize(iterable $headers):array{
 
 		foreach($headers as $key => $val){
 
-			// the key is numeric, so $val is either a string or an array
+			// the key is numeric, so $val is either a string or an array that contains both
 			if(is_numeric($key)){
-				// "key: val"
-				if(is_string($val)){
-					$header = explode(':', $val, 2);
+				[$key, $val] = self::normalizeKV($val);
 
-					if(count($header) !== 2){
-						continue;
-					}
-
-					$key = $header[0];
-					$val = $header[1];
+				if($key === null){
+					continue;
 				}
-				// [$key, $val], ["key" => $key, "val" => $val]
-				elseif(is_array($val) && !empty($val)){
-					$key = array_keys($val)[0];
-					$val = array_values($val)[0];
-
-					// skip if the key is numeric
-					if(is_numeric($key)){
-						continue;
+			}
+
+			$key = self::normalizeHeaderName($key);
+
+			// cookie headers may appear multiple times -  we'll just collect the last value here
+			// https://datatracker.ietf.org/doc/html/rfc6265#section-5.2
+			if($key === 'Set-Cookie'){
+				$name = fn(string $v):string => trim(strtolower(explode('=', $v, 2)[0]));
+
+				// array received from Message::getHeaders()
+				if(is_array($val)){
+					foreach($val as $line){
+						$normalized[$key][$name($line)] = trim($line);
 					}
 				}
 				else{
-					continue;
+					$normalized[$key][$name($val)] = trim($val);
 				}
 			}
-			// the key is named, so we assume $val holds the header values only, either as string or array
+			// combine header fields with the same name
+			// https://datatracker.ietf.org/doc/html/rfc7230#section-3.2
 			else{
+
+				// the key is named, so we assume $val holds the header values only, either as string or array
 				if(is_array($val)){
 					$val = implode(', ', array_values($val));
 				}
-			}
 
-			$key = self::normalizeHeaderName($key);
-			$val = trim((string)($val ?? ''));
+				$val = trim((string)($val ?? ''));
 
-			// skip if the header already exists but the current value is empty
-			if(isset($normalized[$key]) && empty($val)){
-				continue;
-			}
+				// skip if the header already exists but the current value is empty
+				if(isset($normalized[$key]) && empty($val)){
+					continue;
+				}
 
-			// cookie headers may appear multiple times
-			// https://tools.ietf.org/html/rfc6265#section-4.1.2
-			if($key === 'Set-Cookie'){
-				// we'll just collect the last value here and leave parsing up to you :P
-				$normalized[$key][strtolower(explode('=', $val, 2)[0])] = $val;
-			}
-			// combine header fields with the same name
-			// https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
-			else{
-				isset($normalized[$key]) && !empty($normalized[$key])
+				!empty($normalized[$key])
 					? $normalized[$key] .= ', '.$val
 					: $normalized[$key] = $val;
 			}
@@ -90,6 +81,33 @@ public static function normalize(iterable $headers):array{
 		return $normalized;
 	}
 
+	/**
+	 * Extracts a key:value pair from the given value and returns it as 2-element array.
+	 * If the key cannot be parsed, both array values will be `null`.
+	 */
+	protected static function normalizeKV(mixed $value):array{
+
+		// "key: val"
+		if(is_string($value)){
+			$kv = explode(':', $value, 2);
+
+			if(count($kv) === 2){
+				return $kv;
+			}
+		}
+		// [$key, $val], ["key" => $key, "val" => $val]
+		elseif(is_array($value) && !empty($value)){
+			$key = array_keys($value)[0];
+			$val = array_values($value)[0];
+
+			if(is_string($key)){
+				return [$key, $val];
+			}
+		}
+
+		return [null, null];
+	}
+
 	/**
 	 * Trims whitespace from the header values.
 	 *

tests/HeaderUtilTest.php

@@ -48,6 +48,30 @@ public function testNormalizeHeaders(array $headers, array $normalized):void{
 		$this::assertSame($normalized, HeaderUtil::normalize($headers));
 	}
 
+	public function testNormalizeHeadersFromMessageInterface():void{
+
+		$response = $this->responseFactory
+			->createResponse()
+			->withHeader('foo', 'bar')
+			->withAddedHeader('what', 'nope')
+			->withAddedHeader('what', 'why')
+			->withHeader('set-cookie', 'foo=nope')
+			->withAddedHeader('set-cookie', 'foo=bar')
+			->withAddedHeader('set-cookie', 'what=why')
+		;
+
+		$expected = [
+			'Foo'        => 'bar',
+			'What'       => 'nope, why',
+			'Set-Cookie' => [
+				'foo'  => 'foo=bar',
+				'what' => 'what=why',
+			],
+		];
+
+		$this::assertSame($expected, HeaderUtil::normalize($response->getHeaders()));
+	}
+
 	public function testCombineHeaderFields():void{
 
 		$headers = [
@@ -61,23 +85,27 @@ public function testCombineHeaderFields():void{
 			' x-foo ' => ['what', 'nope'],
 		];
 
-		$this::assertSame([
+		$expected = [
 			'Accept'     => 'foo, bar',
 			'X-Whatever' => 'nope',
 			'X-Foo'      => 'bar, baz, what, nope',
-		], HeaderUtil::normalize($headers));
+		];
+
+		$this::assertSame($expected, HeaderUtil::normalize($headers));
 
 		$r = $this->responseFactory->createResponse();
 
 		foreach(HeaderUtil::normalize($headers) as $k => $v){
 			$r = $r->withAddedHeader($k, $v);
 		}
 
-		$this::assertSame([
+		$expected = [
 			'Accept'     => ['foo, bar'],
 			'X-Whatever' => ['nope'],
 			'X-Foo'      => ['bar, baz, what, nope'],
-		], $r->getHeaders());
+		];
+
+		$this::assertSame($expected, $r->getHeaders());
 
 	}