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const DEBUG_all_valid = false;
const DEBUG_all_stub = false;
function handleRequest(request, response) {
// Decode the query string to know what test we're doing.
// character 1: 'I' = text/css response, 'J' = text/html response
let responseCSS = request.queryString[0] == "I";
// character 2: redirection type - we only care about whether we're
// ultimately same-origin with the requesting document ('A', 'D') or
// not ('B', 'C').
let sameOrigin =
request.queryString[1] == "A" || request.queryString[1] == "D";
// character 3: '1' = syntactically valid, '2' = invalid, '3' = http error
let malformed = request.queryString[2] == "2";
let httpError = request.queryString[2] == "3";
// character 4: loaded with <link> or @import (no action required)
// character 5: loading document mode: 'q' = quirks, 's' = standards
let quirksMode = request.queryString[4] == "q";
// Our response contains a CSS rule that selects an element whose
// ID is the first four characters of the query string.
let selector = "#" + request.queryString.substring(0, 4);
// "Malformed" responses wrap the CSS rule in the construct
// <html>{} ... </html>
// This mimics what the CSS parser might see if an actual HTML
// document were fed to it. Because CSS parsers recover from
// errors by skipping tokens until they find something
// recognizable, a style rule appearing where I wrote '...' above
// will be honored!
let leader = malformed ? "<html>{}" : "";
let trailer = malformed ? "</html>" : "";
// Standards mode documents will ignore the style sheet if it is being
// served as text/html (regardless of its contents). Quirks mode
// documents will ignore the style sheet if it is being served as
// text/html _and_ it is not same-origin. Regardless, style sheets
// are ignored if they come as the body of an HTTP error response.
//
// Style sheets that should be ignored paint the element red; those
// that should be honored paint it lime.
let color =
(responseCSS || (quirksMode && sameOrigin)) && !httpError ? "lime" : "red";
// For debugging the test itself, we have the capacity to make every style
// sheet well-formed, or every style sheet do nothing.
if (DEBUG_all_valid) {
// In this mode, every test chip should turn blue.
response.setHeader("Content-Type", "text/css");
response.write(selector + "{background-color:blue}\n");
} else if (DEBUG_all_stub) {
// In this mode, every test chip for a case where the true test
// sheet would be honored, should turn red.
response.setHeader("Content-Type", "text/css");
response.write(selector + "{}\n");
} else {
// Normal operation.
if (httpError) {
response.setStatusLine(request.httpVersion, 500, "Internal Server Error");
}
response.setHeader("Content-Type", responseCSS ? "text/css" : "text/html");
response.write(
leader + selector + "{background-color:" + color + "}" + trailer + "\n"
);
}
}