• About Us
  • Blog
  • Basket
  • Account
  • Sign In
  •  

C API

What's covered

This tutorial illustrates the basic use of the 51Degrees API. It will show you how to create a provider, how to create a dataset and how to obtain a value for the IsMobile property.

Code and Explanation

Getting started example of using 51Degrees device detection. The example shows how to:

  1. Specify name of the data file and properties the dataset should be initialised with.

    const char* fileName = argv[1];
    const char* properties = "IsMobile";
    

  2. Instantiate the 51Degrees provider from the specified data file with the required properties.

    fiftyoneDegreesInitProviderWithPropertyString(
    fileName, &provider, properties);
    

  3. Create a new device offsets structure and use it for a single match.

    fiftyoneDegreesDeviceOffsets *offsets = NULL;
    offsets = fiftyoneDegreesCreateDeviceOffsets;
    

  4. Match a single HTTP User-Agent string to retrieve the values associated with the User-Agent for the selected properties.

    fiftyoneDegreesSetDeviceOffsets(&provider->dataSet, offsets, userAgent);
    

  5. Extract the value of the IsMobile property.

    requiredPropertyIndex = fiftyoneDegreesGetRequiredPropertyIndex(
    	dataSet,
    	"IsMobile");
    isMobile = fiftyoneDegreesGetValuePtrFromOffsets(
    	dataSet,
    	offsets,
    	requiredPropertyIndex);
    }

  6. Free the offsets used for the match.

    fiftyoneDefreesFreeDeviceOffsets(offsets);
    

  7. Finally release the memory taken by the provider.

    fiftyoneDegreesProviderFree(&provider);
    

This example assumes you have compiled with 51Degrees.c. This will happen automatically if you are compiling as part of the Visual Studio solution. Additionally, when running the program, the location of a 51Degrees data file must be passed as a command line argument if you wish to use Premium or Enterprise data files.

This, and any other Trie example can be built to stream from file to reduce memory overhead by defining FIFTYONEDEGREES_INDIRECT at compile time. This encurs a performance penalty due to disk read and cache locking. Currently the caching used for an indirect (file stream) data set does not reserve an entity it has given out, so care should be taken to ensure an entity is not removed from the cache while another thread is using it. This can be done by defining FIFTYONEDEGREES_NO_THREADING and using the provider in a single threaded environment. Alternatively, for a multi threaded environment, the stream caches should be set to a higher number of entries than you expect to be handed out to threads at any one time. This is done by defining: FIFTYONEDEGREES_STRING_CACHE_SIZE, FIFTYONEDEGREES_NODE_CACHE_SIZE, FIFTYONEDEGREES_DEVICE_CACHE_SIZE and FIFTYONEDEGREES_PROFILE_CACHE_SIZE accordingly.

Full Source File
#include <stdio.h>
#include "../src/trie/51Degrees.h"

// Global settings and properties.
static fiftyoneDegreesProvider provider;

// Function declarations.
static void reportDatasetInitStatus(
    fiftyoneDegreesDataSetInitStatus status,
    const char* fileName);

const char* getIsMobile(fiftyoneDegreesDataSet *dataSet, fiftyoneDegreesDeviceOffsets *offsets);
void run(fiftyoneDegreesDataSet* DataSet);

int main(int argc, char* argv[]) {
    const char* properties = "ScreenPixelsWidth,HardwareModel,IsMobile,BrowserName";
    const char* fileName = argc > 1 ? argv[1] : "../../../data/51Degrees-LiteV3.4.trie";

#ifdef _DEBUG
#ifndef _MSC_VER
    dmalloc_debug_setup("log-stats,log-non-free,check-fence,log=dmalloc.log");
#endif
#endif

    // Create a pool of 4 worksets with a cache for 1000 items.
    fiftyoneDegreesDataSetInitStatus status =
        fiftyoneDegreesInitProviderWithPropertyString(
        fileName, &provider, properties);
    if (status != DATA_SET_INIT_STATUS_SUCCESS) {
        reportDatasetInitStatus(status, fileName);
        fgetc(stdin);
        return 1;
    }

    run(provider.active->dataSet);

    // Free the pool, dataset and cache.
    fiftyoneDegreesProviderFree(&provider);

#ifdef _DEBUG
#ifdef _MSC_VER
    _CrtDumpMemoryLeaks();
#else
    printf("Log file is %s\r\n", dmalloc_logpath);
#endif
#endif

    // Wait for a character to be pressed.
    fgetc(stdin);

    return 0;
}

void run(fiftyoneDegreesDataSet* dataSet) {
    const char* isMobile;
    fiftyoneDegreesDeviceOffsets *offsets;

    // User-Agent string of an iPhone mobile device.
    const char* mobileUserAgent = ("Mozilla/5.0 (iPhone; CPU iPhone OS 7_1 like Mac OS X) "
        "AppleWebKit/537.51.2 (KHTML, like Gecko) 'Version/7.0 Mobile/11D167 "
        "Safari/9537.53");

    // User-Agent string of Firefox Web browser version 41 on desktop.
    const char* desktopUserAgent = ("Mozilla/5.0 (Windows NT 6.3; WOW64; rv:41.0) "
        "Gecko/20100101 Firefox/41.0");

    // User-Agent string of a MediaHub device.
    const char* mediaHubUserAgent = ("Mozilla/5.0 (Linux; Android 4.4.2; X7 Quad Core "
        "Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 "
        "Chrome/30.0.0.0 Safari/537.36");

    printf("Starting Getting Started Example.\n");

    offsets = fiftyoneDegreesCreateDeviceOffsets(dataSet);
    offsets->size = 1;

    // Carries out a match for a mobile User-Agent.
    printf("\nMobile User-Agent: %s\n", mobileUserAgent);
    fiftyoneDegreesSetDeviceOffset(dataSet, mobileUserAgent, 0, offsets->firstOffset);
    isMobile = getIsMobile(dataSet, offsets);
    printf("   IsMobile: %s\n", isMobile);

    fiftyoneDegreesResetDeviceOffsets(offsets);
    offsets->size = 1;
    // Carries out a match for a desktop User-Agent.
    printf("\n Desktop User-Agent: %s\n", desktopUserAgent);
    fiftyoneDegreesSetDeviceOffset(dataSet, desktopUserAgent, 0, offsets->firstOffset);
    isMobile = getIsMobile(dataSet, offsets);
    printf("   IsMobile: %s\n", isMobile);

    fiftyoneDegreesResetDeviceOffsets(offsets);
    offsets->size = 1;
    // Carries out a match for a MediaHub User-Agent.
    printf("\n Media hub User-Agent: %s\n", mediaHubUserAgent);
    fiftyoneDegreesSetDeviceOffset(dataSet, mediaHubUserAgent, 0, offsets->firstOffset);
    isMobile = getIsMobile(dataSet, offsets);
    printf("   IsMobile: %s\n", isMobile);

    fiftyoneDegreesFreeDeviceOffsets(offsets);
}

/**
* Returns a string representation of the value associated with the IsMobile
* property.
* @param dataSet initialised data set.
* @param offsets the offsets set by a match.
* @returns a string representation of the value for IsMobile
*/
const char* getIsMobile(fiftyoneDegreesDataSet* dataSet, fiftyoneDegreesDeviceOffsets *offsets) {
    int32_t requiredPropertyIndex;
    const char* isMobile = NULL;
    const char* property = "IsMobile";

    requiredPropertyIndex = fiftyoneDegreesGetRequiredPropertyIndex(dataSet, property);
    if (requiredPropertyIndex >= 0 &&
        requiredPropertyIndex <
        fiftyoneDegreesGetRequiredPropertiesCount(dataSet)) {
        isMobile = fiftyoneDegreesGetValuePtrFromOffsets(
            dataSet,
            offsets,
            requiredPropertyIndex);
    }

    return isMobile;
}

/**
* Reports the status of the data file initialization.
*/
static void reportDatasetInitStatus(fiftyoneDegreesDataSetInitStatus status,
    const char* fileName) {
    switch (status) {
    case DATA_SET_INIT_STATUS_INSUFFICIENT_MEMORY:
        printf("Insufficient memory to load '%s'.", fileName);
        break;
    case DATA_SET_INIT_STATUS_CORRUPT_DATA:
        printf("Device data file '%s' is corrupted.", fileName);
        break;
    case DATA_SET_INIT_STATUS_INCORRECT_VERSION:
        printf("Device data file '%s' is not correct version.", fileName);
        break;
    case DATA_SET_INIT_STATUS_FILE_NOT_FOUND:
        printf("Device data file '%s' not found.", fileName);
        break;
    default:
        printf("Device data file '%s' could not be loaded.", fileName);
        break;
    }
}

Full Source File

Summary

In this tutorial you have seen how to use the detector to retrieve the IsMobile property for a pre-defined User-Agent string. The example can easily be modified to retrieve the value of any other property. Premium and Enterprise data files provide considerably more properties such as IsCrawler, PriceBand, HardwareVendor and ScreenInchesWidth. For a full list of properties and the data file versions they exist in please see the Property Dictionary.