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C API

What's Covered

51Degrees device detector returns all detection results as a string. This tutorial demonstrates how to return results for the IsMobile property value as a boolean.

Code and Explanation

Strongly Typed 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, number of worksets in the pool and cache of the specific size.

    	fiftyoneDegreesInitProviderWithPropertyString(
    	fileName, &provider, properties, 4, 1000);
    	

  3. Retrieve a workset from the pool and use it for a single match.

    	fiftyoneDegreesWorkset *ws = NULL;
    	ws = fiftyoneDegreesProviderWorksetGet(&provider);
    	

  4. Produce a match for a single HTTP User-Agent

    	fiftyoneDegreesMatch(ws, userAgent);
    	

  5. Extract the boolean value of the IsMobile property

    		requiredPropertyIndex = fiftyoneDegreesGetRequiredPropertyIndex
    		(ws->dataSet, "IsMobile");
    		fiftyoneDegreesSetValues(ws, requiredPropertyIndex);
    		valueName = fiftyoneDegreesGetString(ws->dataSet,
    		ws->values[0]->nameOffset);
    		isMobile = &(valueName->firstByte);
    		if (strcmp(isMobile, "True") == 0) {
    			return true;
    		}
    		else {
    			return false;
    		}
    	

  6. Release the workset back into the pool of worksets to be reused in one of the next matches.

    	fiftyoneDegreesWorksetRelease(ws);
    	

  7. Finally release the memory taken by the provider.

    	fiftyoneDegreesProviderFree(&provider);
    	

This example assumes you have compiled with 51Degrees.c and city.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.

The size of the worksets pool parameter should be set to the maximum (expected) number of concurrent detections to avoid delays related to waiting for free worksets. Workset pool is thread safe. Initially the number of created worksets in the pool is zero. When a workset is retrieved from the pool a new workset is created if no worksets are currently free and the number of worksets already created is less than the maximum size of the workset pool.

This example differs from the Getting Started example by using boolean values for the isMobile property instead of string values.

Full Source File
#include "../src/pattern/51Degrees.h"

// Global settings and properties.
static fiftyoneDegreesProvider provider;

// Function declarations.
static void reportDatasetInitStatus(
    fiftyoneDegreesDataSetInitStatus status,
    const char* fileName);
void run(fiftyoneDegreesProvider* provider);
bool getIsMobileBool(fiftyoneDegreesWorkset* ws);

int main(int argc, char* argv[]) {
    const char* properties = "IsMobile";
    const char* fileName = argc > 1 ? argv[1] : "../../../data/51Degrees-LiteV3.2.dat";

#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, 4, 1000);
    if (status != DATA_SET_INIT_STATUS_SUCCESS) {
        reportDatasetInitStatus(status, fileName);
        fgetc(stdin);
        return 1;
    }

    run(&provider);

    // 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(fiftyoneDegreesProvider* provider) {
    bool isMobileBool;
    fiftyoneDegreesWorkset *ws = NULL;

    // 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 Strongly Typed Example\n");

    // Get a workset from the pool to perform this match.
    ws = fiftyoneDegreesProviderWorksetGet(provider);

    // Carries out a match with a mobile User-Agent.
    printf("\nMobile User-Agent: %s\n", mobileUserAgent);
    fiftyoneDegreesMatch(ws, mobileUserAgent);
    isMobileBool = getIsMobileBool(ws);
    if (isMobileBool){
        printf("Mobile\n");
    }
    else {
        printf("Non-Mobile\n");
    }

    // Release workset after match complete and workset no longer required.
    fiftyoneDegreesWorksetRelease(ws);

    // Get a workset from the pool to perform this match.
    ws = fiftyoneDegreesProviderWorksetGet(provider);

    // Carries out a match with a desktop User-Agent.
    printf("\nDesktop User-Agent: %s\n", desktopUserAgent);
    fiftyoneDegreesMatch(ws, desktopUserAgent);
    isMobileBool = getIsMobileBool(ws);
    if (isMobileBool){
        printf("Mobile\n");
    }
    else {
        printf("Non-Mobile\n");
    }

    // Release workset after match complete and workset no longer required.
    fiftyoneDegreesWorksetRelease(ws);

    // Get a workset from the pool to perform this match.
    ws = fiftyoneDegreesProviderWorksetGet(provider);

    // Carries out a match with a MediaHub User-Agent.
    printf("\nMedia hub User-Agent: %s\n", mediaHubUserAgent);
    fiftyoneDegreesMatch(ws, mediaHubUserAgent);
    isMobileBool = getIsMobileBool(ws);
    if (isMobileBool){
        printf("Mobile\n");
    }
    else {
        printf("Non-Mobile\n");
    }

    // Release workset after match complete and workset no longer required.
    fiftyoneDegreesWorksetRelease(ws);
}

/**
 * Returns a boolean representation of the value associated with the IsMobile
 * property.
 * @param initialised workset of type fiftyoneDegreesWorkset
 * @returns a boolean representation of the value for IsMobile
 */
bool getIsMobileBool(fiftyoneDegreesWorkset* ws) {
    int requiredPropertyIndex;
    const char* isMobile;
    const fiftyoneDegreesAsciiString* valueName;

    requiredPropertyIndex = fiftyoneDegreesGetRequiredPropertyIndex(ws->dataSet, "IsMobile");
    fiftyoneDegreesSetValues(ws, requiredPropertyIndex);
    valueName = fiftyoneDegreesGetString(ws->dataSet, ws->values[0]->nameOffset);
    isMobile = &(valueName->firstByte);
    if (strcmp(isMobile, "True") == 0) {
        return true;
    }
    else {
        return false;
    }
}

/**
* 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;
    case DATA_SET_INIT_STATUS_NULL_POINTER:
        printf("Null pointer to the existing dataset or memory location.");
        break;
    case DATA_SET_INIT_STATUS_POINTER_OUT_OF_BOUNDS:
        printf("Allocated continuous memory containing 51Degrees data file "
            "appears to be smaller than expected. Most likely because the"
            " data file was not fully loaded into the allocated memory.");
        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. It sets a boolean value to true or false from the original string value of "True" or "False", making if statements simpler to test.