When working with PHP, you may need to decode encoded words in email headers. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
mb_decode_mimeheader: MIME headers may contain encoded-word segments representing non-ASCII text.
What Is mb_decode_mimeheader in PHP?
Decode encoded words in email headers. MIME headers may contain encoded-word segments representing non-ASCII text.
Syntax:
mb_decode_mimeheader(string $string): string
Parameters and return value: The signature above identifies the arguments and return type where the API has a single call. For topic guides, follow the sequence of calls in the examples. Always distinguish a returned value from an object or variable modified by reference.
Important: Decoding does not guarantee an untrusted header is safe for HTML output; escape it when rendering.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
echo mb_decode_mimeheader("=?UTF-8?B?Q2Fmw6k=?=");
The code focuses on the main operation. MIME headers may contain encoded-word segments representing non-ASCII text.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
echo mb_decode_mimeheader("=?ISO-8859-1?Q?Andr=E9?=");
What changes? Decoding does not guarantee an untrusted header is safe for HTML output; escape it when rendering.
Practical Example: Applying It in an Application
Use the following separate example as a starting point for a small application task. Check any extension or environment requirements below before running it.
<?php
$subjectHeader = "=?UTF-8?B?Q2Fmw6k=?=";
$subject = mb_decode_mimeheader($subjectHeader);
echo "Subject: " . $subject;
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. MIME headers may contain encoded-word segments representing non-ASCII text.
Important Behavior and Edge Cases
- Core behavior: MIME headers may contain encoded-word segments representing non-ASCII text.
- Inputs and results: Decoding does not guarantee an untrusted header is safe for HTML output; escape it when rendering.
- Alternatives: mb_encode_mimeheader() encodes outgoing email header text.
- Compatibility: mbstring is required for mb_* functions.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
mb_decode_mimeheader | Decode encoded words in email headers. |
| Related PHP approach | mb_encode_mimeheader() encodes outgoing email header text. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Decoding does not guarantee an untrusted header is safe for HTML output; escape it when rendering. |
| Confusing this API with a related operation | mb_encode_mimeheader() encodes outgoing email header text. |
| Assuming output is identical across environments | Check return values and required extensions or versions. mbstring is required for mb_* functions. |
Key Takeaways
- mb_decode_mimeheader helps you decode encoded words in email headers.
- MIME headers may contain encoded-word segments representing non-ASCII text.
- Decoding does not guarantee an untrusted header is safe for HTML output; escape it when rendering.
Use mb_decode_mimeheader when you need to decode encoded words in email headers. Start with the first example, compare the second, and adapt the practical example to your inputs. Confirm the return value and environment requirements before adding it to production code.