Initialize the API clients

Initialize the search client and index.

This page documents an earlier version of the API client. For the latest version, see Install the (latest) API clients and Customize the clients.

Before you can index your data or search your Algolia indices, you must initialize a search client with your application ID and API key. You can find both in your Algolia account.

Initialize the search client and index

The search client handles authentication and lets you manage your indices, for example, add data to them, or search them.

C#

SearchClient client = new SearchClient("ALGOLIA_APPLICATION_ID", "ALGOLIA_API_KEY");
SearchIndex index = client.InitIndex("ALGOLIA_INDEX_NAME");

Replace ALGOLIA_INDEX_NAME with the name of the index you want to use. You can find your existing indices in the Algolia dashboard or using the List indices operation. If the index doesn’t exist, a new, empty index is created locally. It’s created on Algolia’s servers only if you add records to the index.

Don’t use sensitive or personally identifiable information as your index name, including usernames, IDs, or email addresses. Index names are publicly shared.

Methods that are scoped to your Algolia applications (methods of a client object):

• Managing indices
• Working with dictionaries
• Working with API keys

Methods that are scoped to an index are:

• Search, indexing, settings, synonyms, and rules methods

The Recommend, Personalization, Insights, and A/B testing APIs have their own clients:

• Recommend API methods
• A/B testing API methods
• Insights API methods
• Personalization API methods

Usage notes

Not all API clients have usage notes.

C#

Serialization

The API client uses Json.NET as the serializer for your POCOs. You can index your POCOs directly if they follow the .NET naming convention.

Example:

C#

using Algolia.Search.Clients;
using Algolia.Search.Models.Search;
using System.Collections.Generic;

public class Contact
{
    public string ObjectID { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}

public class AlgoliaIntegration
{
    private SearchClient client;
    private SearchIndex index;

    public AlgoliaIntegrationService(string applicationId, string apiKey)
    {
        client = new SearchClient(applicationId, apiKey);
        index = client.InitIndex("contact");
    }

    public void SaveContacts(IEnumerable<Contact> contacts)
    {
        // Ensure that contacts is not null and has data
        if (contacts != null)
        {
            index.SaveObjects(contacts);
        }
    }

    public Contact GetContact(string objectId)
    {
        try
        {
            Contact contact = index.GetObject<Contact>(objectId);
            return contact;
        }
        catch (Algolia.Search.Exceptions.AlgoliaApiException ex)
        {
            // Handle exceptions from the Algolia API here
            // Log the exception message: ex.Message
            return null;
        }
    }

    public IEnumerable<Contact> SearchForContact(string queryText)
    {
        try
        {
            var result = index.Search<Contact>(new Query(queryText));
            return result.Hits;
        }
        catch (Algolia.Search.Exceptions.AlgoliaApiException ex)
        {
            // Handle exceptions from the Algolia API here
            // Log the exception message: ex.Message
            return new List<Contact>();
        }
    }
}

// Usage:
// AlgoliaIntegration algoliaService = new AlgoliaIntegration("YourApplicationID", "YourWriteAPIKey");
// IEnumerable<Contact> contacts = ... // Fetch from DB or a Json file
// algoliaService.SaveContacts(contacts);
// Contact contact = algoliaService.GetContact("myId");
// IEnumerable<Contact> searchResult = algoliaService.SearchForContact("contact");

You can override the naming strategy with the following attribute: [JsonProperty(PropertyName = "propertyName")]

You can also add and retrieve records via JObject:

C#

using (StreamReader re = File.OpenText("contacts.json"))
using (JsonTextReader reader = new JsonTextReader(re))
{
   JArray batch = JArray.Load(reader);
   index.SaveObjects(batch).Wait();
}

// Retrieve one JObject Contact
JObject contact = index.GetObject<JObject>("myId");

Algolia objects such as Rule, Synonym, or Settings are now typed.

An example with the Settings class:

C#

IndexSettings settings = new IndexSettings
{
    SearchableAttributes = new List<string> {"attribute1", "attribute2"},
    AttributesForFaceting = new List<string> {"filterOnly(attribute2)"},
    UnretrievableAttributes = new List<string> {"attribute1", "attribute2"},
    AttributesToRetrieve = new List<string> {"attribute3", "attribute4"}
    // etc.
};

index.SetSettings(settings);

If you want to access all properties of the SearchResponse object, you must add these properties to your class. For example, to get the _rankingInfo attribute with your search:

C#

public class Contact
{
  public string ObjectID { get; set; }
  public string Name { get; set; }
  public int Age { get; set; }

  public object _rankingInfo { get; set; }
}

Asynchronous and synchronous methods

The API client provides both synchronous and asynchronous methods for every API endpoint. Asynchronous methods are suffixed with the Async keyword.

C#

// Synchronous
Contact res = index.GetObject<Contact>("myId");

// Asynchronous
Contact res = await index.GetObjectAsync<Contact>("myId");

Custom HTTP clients

The API client uses the built-in HttpClient of the .NET Framework.

The HttpClient is wrapped in an interface: IHttpRequester. If you want to use a custom HttpClient, you can pass it to the constructors of SearchClient, AnalyticsClient, or InsightsClient.

For example:

C#

IHttpRequester myCustomHttpClient = new MyCustomHttpClient();

SearchClient client = new SearchClient(
    new SearchConfig("YourApplicationID", "YourWriteAPIKey"),
    myCustomHttpClient
);

Thread safety

The API client is thread-safe. You can use SearchClient, AnalyticsClient, and InsightsClient in a multi-threaded environment.

Java

JVM DNS caching

By default, the JVM caches DNS resolutions infinitely. Since Algolia uses multiple IP addresses for load balancing, you should reduce the time to live (TTL) of the cache.

For example, to set the cache to 60 seconds:

Java

java.security.Security.setProperty("networkaddress.cache.ttl", "60");

Debug logging

To enable debug logging in the API client, add the following line to your logging.properties file:

XML

com.algolia.search.HttpTransport=FINEST

Builder

The Java API client comes in two packages:

• algoliasearch-core which implements the API methods, Java objects, transport layer, and retry strategy. This package is HTTP client agnostic.
• algoliasearch-apache, algoliasearch-jvm-net are HTTP client implementations of the core library.

If you want to use your own HTTP client, inject it into all client classes of the library. Your custom HTTP client must implement the HttpRequester interface.

If you’re using a custom HTTP client, you don’t need to use algoliasearch-apache or algoliasearch-jvm-net as a dependency.

Java

SearchConfig config =
new SearchConfig.Builder("YourApplicationID", "YourWriteAPIKey")
    .build();

HttpRequester myCustomRequester = new myCustomRequester();

SearchClient client = new SearchClient(config, myCustomRequester);

All clients are safe to use as singletons. Reuse client instances as much as possible to avoid exhausting the number of available sockets. All clients implement the Closeable interface: close them when you’re done using them.

Serialization

You can parametrize the SearchIndex class with a Java class which lets you use type-safe method results.

The parametrized Java classes should follow the POJO convention:

• A constructor without parameters
• Getters and setters for every field you want to (de)serialize

For example:

Java

public class Contact {

  private String name;
  private int age;

  public Contact() {}

  public String getName() {
    return name;
  }

  public Contact setName(String name) {
    this.name = name;
    return this;
  }

  public int getAge() {
    return age;
  }

  public Contact setAge(int age) {
    this.age = age;
    return this;
  }
}

The Java API client uses Jackson2 for serialization and deserialization. The default object mapper is set in: com.algolia.search.Defaults.DEFAULT_OBJECT_MAPPER.

Asynchronous methods and completable futures

All asynchronous methods have the suffix Async and are defined in the same classes as their synchronous counterparts. Asynchronous methods return a CompletableFuture.

You can also pass a custom ExecutorService to the Configuration builder. By default, the API client uses ForkJoinPool.commonPool.

Thread safety

The Java API clients are thread-safe. You can use SearchClient, AnalyticsClient, and InsightsClient in multi-threaded environments.

Handling exceptions

The Java API clients can throw three types of runtime exceptions:

• AlgoliaApiException: when Algolia APIs send back an HTTP error code
• AlgoliaRetryException: when the retry strategy failed to target all hosts
• AlgoliaRuntimeException: when an error occurred during serialization/deserialization or data processing
• IllegalArgumentException: when you provide invalid parameters
• NullPointerException: when you pass a null pointer

Proxies

To run the API client behind a proxy, you can set the following properties at the JVM level:

Java

System.setProperty("https.proxyHost", "https host");
System.setProperty("https.proxyPort", "https port");
System.setProperty("https.proxyUser", "https proxy login");
System.setProperty("https.proxyPassword", "https proxy password");

SearchConfig config = new SearchConfig.Builder("YourApplicationID", "YourWriteAPIKey")
    .setUseSystemProxy(true)
    .build();

SearchClient client = DefaultSearchClient.create(config);

For more information about JVM proxy settings, see the Java documentation.

Kotlin

Type safety

Response and parameters objects are typed to provide extensive compile-time safety. For example, to initialize the API client without confusing application ID and the API key:

Kotlin

val appID = ApplicationID("YourApplicationID")
val apiKey = APIKey("YourWriteAPIKey")

val client = ClientSearch(appID, apiKey)

For example, to use typed attributes:

Kotlin

val color = Attribute("color")
val category = Attribute("category")
val query = Query(attributesToRetrieve = listOf(color, category))

Enumerated types are represented by sealed classes. This lets you quickly discover all possible values for each type. Each enumerated type includes Other to pass a custom value:

Kotlin

val query = Query()

query.sortFacetsBy = SortFacetsBy.Count
// query.sortFacetsBy = SortFacetsBy.Alpha
// query.sortFacetsBy = SortFacetsBy.Other("custom value")

Domain-specific language

The Kotlin API client lets you use a domain-specific language (DSL) to set parameters, configure your index, or use filters for your search:

Example for query parameters:

Kotlin

val query = query {
   attributesToRetrieve {
       +"color"
       +"category"
   }
}

Example for settings:

Kotlin

val settings = settings {
   attributesToSnippet {
       +"content"(10)
   }
}

Example for filters:

Kotlin

val query = query {
   filters {
       and {
           facet("color", "red")
           facet("category", "shirt")
       }
       orNumeric {
           range("price", 0 until 10)
           comparison("price", Equals, 15)
       }
   }
}

Serialization

The Kotlin API client uses the kotlinx serialization library.

Deserialize a search response

To deserialize results from a search response, use the deserialize extension functions.

Kotlin

@Serializable
data class Contact(
    val firstname: String,
    val lastname: String
)

val response = index.search()
val contacts: List<Contact> = response.hits.deserialize(Contact.serializer())

Deserialize response from getObject

To deserialize the response from getObject, pass serializer as a parameter.

Kotlin

@Serializable
data class Contact(
    val firstname: String,
    val lastname: String,
    override val objectID: ObjectID
) : Indexable

val objectID = ObjectID("myID1")
val contact: Contact = index.getObject(Contact.serializer(), objectID)

Serialize and deserialize any Kotlin object

Use the standard methods of the kotlinx serialization library.

Kotlin

@Serializable
data class Contact(
    val firstname: String,
    val lastname: String
)

// Create a new JSON object
val json: JsonObject = buildJsonObject {
    put("firstname", "Jimmie")
    put("lastname", "Barninger")
}

// Transform the JSON object into a Kotlin object
val contact: Contact = Json.decodeFromJsonElement(Contact.serializer(), json)

// You can configure your own `Json` instance for custom options:
val JsonNonStrict = Json {
    ignoreUnknownKeys = true
    isLenient = true
    allowSpecialFloatingPointValues = true
}
val contactNonStrict: Contact = JsonNonStrict.decodeFromJsonElement(Contact.serializer(), json)

Handling exceptions

A successful HTTP call returns a typed response object:

Kotlin

val response: ResponseSearch = index.search()

To handle exceptions, use a try / catch block:

Kotlin

try {
    val response = index.search()
} catch (exception: AlgoliaApiException) {
    when (exception.httpErrorCode) {
        404 -> TODO()
        400 -> TODO()
    }
}

Use multiple catch blocks to handle different types of exceptions:

Kotlin

try {
    val response = index.search()
} catch (exception: AlgoliaRuntimeException) {
    TODO()
} catch (exception: IOException) {
    TODO()
} catch (exception: Exception) {
    TODO()
}

Coroutines

The Kotlin API client uses suspending functions for all HTTP calls. This means that you can call these functions only from a coroutine scope.

The following example starts a coroutine in the main thread, then performs the search HTTP call in another thread. You can change the search response from the main thread.

Kotlin

class Searcher : CoroutineScope {
    override val coroutineContext = SupervisorJob()

    fun search() {
        launch(Dispatchers.Main) {
            val response = withContext(Dispatchers.Default) { index.search() }
        }
    }
}

The Kotlin API client doesn’t run any HTTP calls on any particular thread. You need to define this explicitly using coroutines.

To learn more about coroutines, see the Kotlin documentation.

Waiting for operations

Many operations with Algolia are asynchronous. To wait for operations, use apply or run:

Kotlin

index.apply {
    setSettings(Settings()).wait()
}
client.run {
    multipleBatchObjects(listOf<BatchOperationIndex>()).waitAll()
}

The wait functions are suspense functions and should be called from coroutines.

Thread safety

The Kotlin API client is thread-safe. You can use SearchClient, AnalyticsClient, and InsightsClient in a multi-threaded environment.

Python

Asynchronous methods

To use the Python API client in asynchronous environment, install these extra dependencies:

python -m pip install "asyncio>=3.4,<4.0" "aiohttp>=2.0,<4.0" "async_timeout>=2.0,<4.0"

The asynchronous methods have an _async prefix.

Sync	Async
search	search_async
save_objects	save_objects_async
set_settings	set_settings_async
save_synonyms	save_synonyms_async

The following example creates a new index and adds two test records to it asynchronously.

Python

import asyncio

from algoliasearch.search_client import SearchClient

app_id = "ALGOLIA_APPLICATION_ID"
api_key = "ALGOLIA_API_KEY"


async def main():
    async with SearchClient.create(app_id, api_key) as client:
        index = client.init_index("ALGOLIA_INDEX_NAME")

        response = await index.save_objects_async(
            [{"objectID": 1, "name": "foo"}, {"objectID": 2, "name": "bar"}]
        )

        results = await index.search_async("")

        print(results)

    asyncio.run(main())

Scala

JVM DNS caching

By default, the JVM caches DNS resolutions infinitely. Since Algolia uses multiple IP addresses for load balancing, you should reduce the time to live (TTL) of the cache.

For example, to set the cache to 60 seconds:

Java

java.security.Security.setProperty("networkaddress.cache.ttl", "60");

Debug logging

You can enable debug logging in the API client using the slf4j library. The logger is named algoliasearch.

Domain-specific language

The Scala API client lets you use a domain-specific language (DSL). The entry point of the DSL is the algolia.AlgoliaDSL object. This DSL is used in the execute method of algolia.AlgoliaClient.

The DSL is designed to be human-readable. For some tasks there may be more than one way of achieving it. For example, to get an object by its objectID:

Scala

client.execute { from index "index" objectId "myId" }
// or
client.execute { get / "index" / "myId" }

Futures

The execute method always returns a scala.concurrent.Future. The Future can be parametrized by a case class:

Scala

val future: Future[Search] =
    client.execute {
        search into "index" query "a"
    }

JSON as case class

The Scala API client uses json4s to serialize and deserialize objects and API responses and case classes.

For example, to deserialize a search response:

Scala

case class Contact(firstname: String,
                   lastname: String,
                   followers: Int,
                   company: String)

val future: Future[Seq[Contact]] =
    client
        .execute {
            search into "index" query "a"
        }
        .map { search =>
            search.as[Contact]
        }

To get the full results from the response:

Scala

case class EnhanceContact(firstname: String,
                          lastname: String,
                          followers: Int,
                          company: String,
                          objectID: String,
                          _highlightResult: Option[Map[String, HighlightResult]],
                          _snippetResult: Option[Map[String, SnippetResult]],
                          _rankingInfo: Option[RankingInfo]) extends Hit

val future: Future[Seq[EnhanceContact]] =
    client
        .execute {
            search into "index" query "a"
        }
        .map { search =>
            search.asHit[EnhanceContact]
        }

When you index your data, pass an instance of your case class to the DSL:

Scala

client.execute {
    index into "contacts" `object` Contact("Jimmie", "Barninger", 93, "California Paint")
}