Go/Golang package for parsing user agent strings

Use useragent.Parse(userAgent string) function to parse browser's and bot's user agents strings and get:

• User agent name and version (Chrome, Firefox, Googlebot, etc.)
• Operating system name and version (Windows, Android, iOS etc.)
• Device type (mobile, desktop, tablet, bot)
• Device name if available (iPhone, iPad, Huawei VNS-L21)
• URL provided by the bot (http://www.google.com/bot.html etc.)

Status

Stable. I use it on high traffic websites on every single request, as well on my Lite Analytics service.

I constantly improve user agents detection and performance. Fill free to report an issue for any User-Agent string not recognized or misinterpreted.

Installation

go get github.com/mileusna/useragent

Example

package main

import (
    "fmt"
    "strings"

    "github.com/mileusna/useragent"
)

func main() {
    userAgents := []string{
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/603.3.8 (KHTML, like Gecko) Version/10.1.2 Safari/603.3.8",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36",
        "Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_2 like Mac OS X) AppleWebKit/603.2.4 (KHTML, like Gecko) Version/10.0 Mobile/14F89 Safari/602.1",	
        "Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_2 like Mac OS X) AppleWebKit/603.2.4 (KHTML, like Gecko) FxiOS/8.1.1b4948 Mobile/14F89 Safari/603.2.4",
        "Mozilla/5.0 (iPad; CPU OS 10_3_2 like Mac OS X) AppleWebKit/603.2.4 (KHTML, like Gecko) Version/10.0 Mobile/14F89 Safari/602.1",
        "Mozilla/5.0 (Linux; Android 4.3; GT-I9300 Build/JSS15J) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.125 Mobile Safari/537.36",
        "Mozilla/5.0 (Android 4.3; Mobile; rv:54.0) Gecko/54.0 Firefox/54.0",
        "Mozilla/5.0 (Linux; Android 4.3; GT-I9300 Build/JSS15J) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.91 Mobile Safari/537.36 OPR/42.9.2246.119956",
        "Opera/9.80 (Android; Opera Mini/28.0.2254/66.318; U; en) Presto/2.12.423 Version/12.16",
    }

    for _, s := range userAgents {
        ua := useragent.Parse(s)
        fmt.Println()
        fmt.Println(ua.String)
        fmt.Println(strings.Repeat("=", len(ua.String)))
        fmt.Println("Name:", ua.Name, "v", ua.Version)
        fmt.Println("OS:", ua.OS, "v", ua.OSVersion)
        fmt.Println("Device:", ua.Device)
        if ua.Mobile {
            fmt.Println("(Mobile)")
        }
        if ua.Tablet {
            fmt.Println("(Tablet)")
        }
        if ua.Desktop {
            fmt.Println("(Desktop)")
        }
        if ua.Bot {
            fmt.Println("(Bot)")
        }
        if ua.URL != "" {
            fmt.Println(ua.URL)
        }
    }
}

Shorthand functions

Beside UserAgent{} struct and its properties returned by useragent.Parse(), there is a bunch of shorthand functions for most popular browsers and operating systems, so this code:

    ua := useragent.Parse(userAgentString)
    if ua.OS == "Android" && ua.Name == "Chrome" {
        // do something
    }

can be also written on this way:

    ua := useragent.Parse(userAgentString)
    if ua.IsAndroid() && ua.IsChrome() {
        // do something
    }

Version parsing

Since v1.3.4, the package also parses the version strings of the Browser and OS into the VersionNo struct. The raw version string from the user agent might look something like 100.0.4896.127. Although this is the full version string, it may not be suitable for various checks you might need to perform in your web services.

To address this, the version strings are parsed into their individual components. After parsing, you can easily check each segment of the version string (e.g., Major, Minor, Patch). For example:

    if ua.IsChrome() && ua.VersionNo.Major < 100 {
        log.Println("Error, browser is too old")
    }

This also makes it easy to print prettified version strings in logs or other outputs. You can use the VersionNoShort() and VersionNoFull() functions for browsers, and OSVersionNoShort() and OSVersionNoFull() for the OS.

    fmt.Println(ua.Name, ua.VersionNoShort())
    fmt.Println(ua.Name, ua.VersionNoFull())
    // output:
    //  Chrome 100.0
    //  Chrome 100.0.4896

Notices

• If Googlebot (or any other bot) is detected and it is using its mobile crawler, both bot and mobile flags will be set to true.
• Opera and Opera Mini are two browsers, since they operate on very different ways.
• This package uses a deterministic method to detect the user agent, even when the user agent string does not follow common formats. However, in some cases, the user agent string may contain very limited information, making it impossible for the package to accurately identify the user agent. In such cases, the function IsUnknown() will return true. Note, however, that struct fields such as Name, OS, and others might still contain partial values.