Personal Catalogue: PHP & MySQL — Chapter 10, Exercise 3
====================================================

TASK
Build api_search.php from this chapter, visit it directly in a
browser with a real search term (e.g. api_search.php?q=Python),
and confirm the response is genuine, valid JSON — not an HTML page
— by checking the response's own Content-Type header and validating
the body with a JSON linter or a small PHP one-liner.

SOLUTION

With api_search.php built exactly as shown in the chapter (including
the header('Content-Type: application/json') call before any output),
and at least one real item in the database with "Python" in its title
or creator (e.g. "Fluent Python" from earlier chapters), visit:

    api_search.php?q=Python

Checking the response headers, e.g. via curl:

    curl -i "http://localhost/catalogue/api_search.php?q=Python"

Expected output includes a header line:

    Content-Type: application/json

confirming the response is genuinely declared as JSON, not the
default text/html PHP would send otherwise.

Checking the response body itself is valid JSON:

    curl -s "http://localhost/catalogue/api_search.php?q=Python" | php -r 'var_dump(json_decode(file_get_contents("php://stdin"), true));'

Expected output: a real PHP array structure printed by var_dump(),
something like:

    array(1) {
      [0]=>
      array(3) {
        ["id"]=>
        int(1)
        ["title"]=>
        string(13) "Fluent Python"
        ["creator"]=>
        string(16) "Luciano Ramalho"
      }
    }

If json_decode() had failed (e.g. because the response wasn't
actually valid JSON), var_dump() would print NULL instead of a real
array — confirming the body parses correctly is what proves it's
genuine JSON, not just text that happens to look JSON-like.

WHY THIS WORKS AS AN ANSWER
----------------------------
It checks both the declared Content-Type header and the actual
parseability of the response body — two genuinely separate things,
since a server can claim application/json while sending malformed
text — rather than only eyeballing the response and assuming it looks
correct.