Practical Web Data Patterns

Header Labels

Turn a request header value into a simple label.

header-label Request headers can influence response behavior, but static examples should model them with local scalar values.

Header Labels

accept
header_label.php
Replay: real traced execution (multi-file project)
<?php
$accept = "json";
$contentType = "text/plain";

if ($accept === "json") {
    $contentType = "application/json";
} elseif ($accept === "html") {
    $contentType = "text/html";
}

echo "accept=" . $accept . "\n";
echo "contentType=" . $contentType . "\n";

<?php
$accept = "html";
$contentType = "text/plain";

if ($accept === "json") {
    $contentType = "application/json";
} elseif ($accept === "html") {
    $contentType = "text/html";
}

echo "accept=" . $accept . "\n";
echo "contentType=" . $contentType . "\n";

<?php
$accept = "text";
$contentType = "text/plain";

if ($accept === "json") {
    $contentType = "application/json";
} elseif ($accept === "html") {
    $contentType = "text/html";
}

echo "accept=" . $accept . "\n";
echo "contentType=" . $contentType . "\n";

  1. $accept ← json, $contentType ← text/plain

    1<?php2$accept→ json = "json"; //@accept="html", "text"3$contentType→ text/plain = "text/plain";

  2. $contentType ← application/json

    5if ($acceptjson === "json") {6    $contentType→ application/json = "application/json";7} elseif ($accept === "html") {

  3. echo "accept=" . $accept . " ";

    11echo "accept=" . $acceptjson . "\n";12echo "contentType=" . $contentTypeapplication/json . "\n";
    outputaccept=json
contentType=application/json

  1. $accept ← html, $contentType ← text/plain

    1<?php2$accept→ html = "html";3$contentType→ text/plain = "text/plain";45if ($accept === "json") {6    $contentType = "application/json";7} elseif ($accept === "html") {8    $contentType→ text/html = "text/html";9}1011echo "accept=" . $accepthtml . "\n";12echo "contentType=" . $contentTypetext/html . "\n";
    outputaccept=html
contentType=text/html

  1. $accept ← text, $contentType ← text/plain

    1<?php2$accept→ text = "text";3$contentType→ text/plain = "text/plain";45if ($accept === "json") {6    $contentType = "application/json";7} elseif ($accept === "html") {8    $contentType = "text/html";9}1011echo "accept=" . $accepttext . "\n";12echo "contentType=" . $contentTypetext/plain . "\n";
    outputaccept=text
contentType=text/plain