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What's Covered

This tutorial illustrates how to append a CSV file containing User-Agent strings with IsMobile, PlatformName and PlatformVersion properties. The following aspects of the API are covered:

  • How to perform a User-Agent match.
  • How to reuse resources to perform subsequent matching.
  • How to retrieve match results for a specific property.
  • How to append a property value to a CSV file.

Code and Explanation

Offline processing example of using 51Degrees Hash Trie device detection. The example shows how to:

  1. Instantiate the 51Degrees device detection provider. 

    										
var provider = FiftyOneDegreesTrieV3.NewProvider(dataFile)
  2. Open an input file with a list of User-Agents, and an output file. 

    										
fin, err := os.Open("20000 User Agents.csv")
fout, err := os.Create(outputFile)
  3. Write a header to the output file with the property names in '|' separated CSV format ('|' separated because some User-Agents contain commas) 

    										
var out = [][]string{{"User-Agent"}}
for i := range properties {
	out[0] = append(out[0], properties[i])
}
  4. For the User-Agents in the input file, perform a match then write the User-Agent along with the values for chosen properties to the csv. 

    										
for _,record := range records{
	// Perform a match on each record and append to an array.
	if len(record) > 0 {
		// Get the User-Agent from each record.
		ua := record

		// Used to store and access detection results.
		match := provider.GetMatch(ua)
		result := []string{ua}

		// Get value for each requested property and append to results.
		for i := range properties{
			result = append(result, match.GetValue(properties[i]))
		}
		out = append(out, result)
		// Close the match object.
		FiftyOneDegreesTrieV3.DeleteMatch(match)
	}
}
This example assumes you have the 51Degrees Go API installed correctly, and have access to a source of User-Agents: "../data/20000 User Agents.csv" and a binary data file: "../data/51Degrees-LiteV3.2.dat". The output directory must also exist and have write permissions.
Full Source File 
									
package main

import (
    "fmt"
    "./src/trie"
    "encoding/csv"
    "os"
    "log"
    "io"
)

// Locations of data files.
const dataFile = "../data/51Degrees-LiteV3.4.trie"
const inputFile = "../data/20000 User Agents.csv"
const outputFile = "offlineProcessingOutput.csv"

// Number of records in the CSV file to process.
const numRecords = 20

// Provides access to device detection functions.
var provider =
    FiftyOneDegreesTrieV3.NewProvider(dataFile)

// Which properties to retrieve
var properties = []string{"IsMobile", "PlatformName", "PlatformVersion"}

func output_offline_processing() {

    // Set csv up reader
    fin, err := os.Open(inputFile)
    if err != nil{
        log.Fatal(err)
    }
    r := csv.NewReader(fin)
    // Separator between records in the input csv file is a pipe, this is 
    // because User-Agents can contain commas.
    r.Comma = '|'
    r.LazyQuotes = true

    // Set csv up writer
    fout, err := os.Create(outputFile)
    if err != nil {
        log.Fatal("Unable to create output file.")
    }
    w := csv.NewWriter(fout)
    // Set separator in output file to the pipe character, this is because
    // User-Agents can contain commas.
    w.Comma = '|'
    defer fout.Close()


    // Create a 2D array to append the match results to so we can write later.
    var out = [][]string{{"User-Agent"}}
    for i := range properties {
        out[0] = append(out[0], properties[i])
    }

    var records []string
    // Read a set number records from input file.
    if numRecords != -1 {
        for i := 0; i < numRecords; i++ {
            record, err := r.Read()
            // Stop at EOF.
            if err == io.EOF {
                break
            }
            // The first part of each record is the User-Agent, append it to
            // records array.
            records = append(records, record[0])
        }
    // Read all records from the input file.
    }else {
        // Read all the records
        record, _ := r.ReadAll()
        // The first part of each record is the User-Agent, append it to
        // records array.
        for i := range record{
            records = append(records, record[i][0])
        }
    }

    // Process all records
    for _,record := range records{
        // Perform a match on each record and append to an array.
        if len(record) > 0 {
            // Get the User-Agent from each record.
            ua := record

            // Used to store and access detection results.
            match := provider.GetMatch(ua)
            result := []string{ua}

            // Get value for each requested property and append to results.
            for i := range properties{
                result = append(result, match.GetValue(properties[i]))
            }
            out = append(out, result)
            // Close the match object.
            FiftyOneDegreesTrieV3.DeleteMatch(match)

        }
    }
    fmt.Println("Done")

    // Write all processed records to the output file.
    w.WriteAll(out)

    defer w.Flush()
    fmt.Println()
}

func main() {
    fmt.Println("Starting Offline Prosessing")
    output_offline_processing()
    fmt.Println("Output file written to ", outputFile)
}
Full Source File

Summary

Offline device detection is frequently required for a variety of reasons such as generating reports. The example is based on an actual support request where several properties had to be added to the CSV file before it could be passed on for another department to use.

This tutorial covered how to use the detector offline to append the first 20 lines of a CSV file with Lite properties: IsMobile , PlatformName and PlatformVersion . Using a Premium or an Enterprise data file gives you access to a far greater number of properties including HardwareVendor , PriceBand , ScreenInchesWidth , IsCrawler and more. A full list of properties and the data file version they are present in can be viewed in the Property Dictionary .

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