why url encoding is required

URL encoding, also known as percent encoding, is a mechanism for encoding information in a Uniform Resource Locator (URL) under certain circumstances. It involves replacing unsafe ASCII characters with a "%" followed by two hexadecimal digits that represent the ASCII value of the character. URL encoding is required for several reasons:

1. Handling Reserved Characters: URLs have certain characters, such as ?, &, #, =, and /, that serve specific purposes in the URL scheme. For example, ? is used to start a query string, and & separates multiple query parameters within that string. If these characters are used in other contexts (e.g., within a parameter value), they could break the URL format. URL encoding lets you safely include these characters in URLs without them being interpreted in their special roles.

2. Non-ASCII Characters: URLs are transmitted over the Internet using the ASCII character-set. If a URL includes characters outside the ASCII set (like characters from other languages, or graphical symbols), they need to be encoded to fit into the ASCII format. This ensures that the URL can be reliably transmitted between computers and interpreted correctly regardless of differences in character encoding standards.

3. Unsafe Characters: Some characters may be unsafe to use in URLs because they could be used to manipulate the URL in malicious ways or might be altered (or misinterpreted) during transmission. Characters like spaces, quotation marks, <, >, and others can be problematic in URLs. Encoding these characters protects the integrity of the URL and ensures that it is not tampered with or corrupted.

4. Uniformity and Consistency: URL encoding provides a consistent method for browsers and servers to exchange information. It ensures that data sent via URLs is uniform and can be interpreted correctly by any server regardless of the platform, language, or settings.

5. Data Submission: Often data is submitted through URLs, especially in GET method forms where form data is appended to the URL. Encoding allows this data to be cleanly separated from other parts of the URL and correctly parsed by the server.

Here is how URL encoding works:

• A URL is composed of a restricted set of characters belonging to the ASCII character set. These characters include digits (0-9), letters (A-Z, a-z), and a few special characters ("-","_",".","~").

• Any character outside this set needs to be encoded — typically those that do not have a direct representation in ASCII or could disrupt the structure of the URL.

• During encoding, characters are replaced with % followed by their two-digit hexadecimal representation. For example, a space character (which is ASCII code 32) is replaced by %20.

URL encoding ensures that all types of data can be included in URLs safely and consistently, making it a fundamental aspect of web browsing and data exchange over the Internet.