GreyCat User-Agent Library

@library("useragent", "0.0.0");

HTTP User-Agent string parser for GreyCat. Extracts browser, operating system, and device information from User-Agent headers — useful for web analytics, compatibility detection, and device-specific content delivery.

Quick Start

var ua = UserAgent::parse(
    "Mozilla/5.0 (Linux; Android 4.4.2; QMV7A Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.135 Safari/537.36"
);

info("Browser: ${ua.browserFamily} ${ua.browserMajor}.${ua.browserMinor}");  // Chrome 36.0
info("OS: ${ua.osFamily} ${ua.osMajor}.${ua.osMinor}.${ua.osPatch}");       // Android 4.4.2
info("Device: ${ua.deviceBrand} ${ua.deviceFamily}");                         // Generic_Android_Tablet QMV7A

API Reference

`UserAgent`

Parsed User-Agent information containing browser, OS, and device details.

Static Methods:

Method	Returns	Description
`UserAgent::parse(userAgent)`	`UserAgent`	Parse a User-Agent string into its components

Browser Fields:

Field	Type	Example	Description
`browserFamily`	`String?`	`"Chrome"`	Browser name
`browserMajor`	`String?`	`"36"`	Major version
`browserMinor`	`String?`	`"0"`	Minor version
`browserPatch`	`String?`	`"1985"`	Patch version

OS Fields:

Field	Type	Example	Description
`osFamily`	`String?`	`"Android"`	Operating system name
`osMajor`	`String?`	`"4"`	Major version
`osMinor`	`String?`	`"4"`	Minor version
`osPatch`	`String?`	`"2"`	Patch version
`osPatchMinor`	`String?`	`null`	Minor patch version

Device Fields:

Field	Type	Example	Description
`deviceFamily`	`String?`	`"QMV7A"`	Device name
`deviceBrand`	`String?`	`"Generic_Android_Tablet"`	Device brand or category
`deviceModel`	`String?`	`"QMV7A"`	Device model identifier

All fields are nullable — values are null when the parser cannot extract them from the User-Agent string.

Examples

Parsing Different User-Agents

// Android tablet
var ua = UserAgent::parse(
    "Mozilla/5.0 (Linux; Android 4.4.2; QMV7A Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.135 Safari/537.36"
);
Assert::equals(ua.browserFamily, "Chrome");
Assert::equals(ua.browserMajor, "36");
Assert::equals(ua.browserMinor, "0");
Assert::equals(ua.browserPatch, "1985");
Assert::equals(ua.osFamily, "Android");
Assert::equals(ua.osMajor, "4");
Assert::equals(ua.osMinor, "4");
Assert::equals(ua.osPatch, "2");
Assert::equals(ua.osPatchMinor, null);
Assert::equals(ua.deviceFamily, "QMV7A");
Assert::equals(ua.deviceBrand, "Generic_Android_Tablet");
Assert::equals(ua.deviceModel, "QMV7A");

Web Analytics — Counting Browsers

fn trackUserAgent(raw: String, browserCounts: Map<String, int>) {
    var ua = UserAgent::parse(raw);
    var browser = ua.browserFamily ?? "Unknown";
    browserCounts.set(browser, (browserCounts.get(browser) ?? 0) + 1);
}

Device-Specific Logic

fn isMobile(raw: String): bool {
    var ua = UserAgent::parse(raw);
    var os = ua.osFamily ?? "";
    return os == "Android" || os == "iOS";
}