Documentation
Install With Maven:
<dependencyManagement>
<dependencies>
<!-- https://mvnrepository.com/artifact/com.konghq/unirest-java-bom -->
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-java-bom</artifactId>
<version>4.3.0</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<!-- https://mvnrepository.com/artifact/com.konghq/unirest-java-core -->
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-java-core</artifactId>
</dependency>
<!-- pick a JSON module if you want to parse JSON include one of these: -->
<!-- Google GSON -->
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-modules-gson</artifactId>
</dependency>
<!-- OR maybe you like Jackson better? -->
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-modules-jackson</artifactId>
</dependency>
</dependencies>
Upgrading from Previous Versions
See the Upgrade Guide
ChangeLog
See the Change Log for recent changes.
Requests
So you’re probably wondering how using Unirest makes creating requests in Java easier, here is a basic POST request that will explain everything:
HttpResponse<JsonNode> response = Unirest.post("http://localhost/post")
.header("accept", "application/json")
.queryString("apiKey", "123")
.field("parameter", "value")
.field("firstname", "Gary")
.asJson();
Requests are made when as[Type]()
is invoked, possible types include Json
, String
, Object
Empty
and File
.
Route Parameters
Sometimes you want to add dynamic parameters in the URL, you can easily do that by adding a placeholder in the URL, and then by setting the route parameters with the routeParam
function, like:
Unirest.get("http://localhost/{fruit}")
.routeParam("fruit", "apple")
.asString();
// Results in `http://localhost/apple`
The placeholder {fruit}
will be replaced with apple
.
The placeholder’s format is as easy as wrapping in curly braces: {custom_name}
All param values will be URL-Encoded for you
Default Base URLs
You can configure a default base URL to be used for all requests that do not contain a full URL.
This configuration will result in a GET to “http://homestar.com/runner”
Unirest.config().defaultBaseUrl("http://homestar.com");
Unirest.get("/runner").asString();
Query Parameters
Query-string params can be built up one by one
Unirest.get("http://localhost")
.queryString("fruit", "apple")
.queryString("droid", "R2D2")
.asString();
// Results in "http://localhost?fruit=apple&droid=R2D2"
Again all param values will be URL-Encoded.
You can also pass in query strings as arrays and maps:
Unirest.get("http://localhost")
.queryString("fruit", Arrays.asList("apple", "orange"))
.queryString(ImmutableMap.of("droid", "R2D2", "beatle", "Ringo"))
.asString();
// Results in "http://localhost?fruit=apple&fruit=orange&droid=R2D2&beatle=Ringo"
Headers
Request headers can be added with the header
method.
Unirest.get("http://localhost")
.header("Accept", "application/json")
.header("x-custom-header", "hello")
.asString();
Basic Authentication
Unirest exposes a shortcut for doing basic auth when you need to. Unirest handles the Base64 encoding part. Please make sure you are always doing this over HTTPS!
Unirest.get("http://localhost")
.basicAuth("user", "password1!")
.asString();
// this adds the header "Authorization: Basic dXNlcjpwYXNzd29yZDEh"
Body Data
Entity Bodies
You can post entity objects as the full body easily. This is the default behavior of most REST services.
Unless you specify otherwise the default Content-Type
is text/plain; charset=UTF-8
Unirest.post("http://localhost")
.body("This is the entire body")
.asEmpty();
You can also post as a Object that is serialized using a configured ObjectMapper. (see Object Mappers for implementation details. Unirest comes with a default mapper that will serialize to json using the popular Google Gson library
Unirest.post("http://localhost")
.header("Content-Type", "application/json")
.body(new SomeUserObject("Bob"))
.asEmpty();
// This will use Jackson to serialize the object into JSON.
JSON Patch Bodies
Unirest has full native support for JSON Patch requests (RFC-6902 see http://jsonpatch.com/)
Per the spec, the default Content-Type
for json-patch is application/json-patch+json
Unirest.jsonPatch("http://localhost")
.add("/fruits/-", "Apple")
.remove("/bugs")
.replace("/lastname", "Flintstone")
.test("/firstname", "Fred")
.move("/old/location", "/new/location")
.copy("/original/location", "/new/location")
.asJson();
will send a request with a body of
[
{"op":"add","path":"/fruits/-","value":"Apple"},
{"op":"remove","path":"/bugs"},
{"op":"replace","path":"/lastname","value":"Flintstone"},
{"op":"test","path":"/firstname","value":"Fred"},
{"op":"move","path":"/new/location","from":"/old/location"},
{"op":"copy","path":"/new/location","from":"/original/location"}
]
Basic Forms
Basic http name value body params can be passed with simple field calls.
The Content-Type
for this type of request is defaulted to application/x-www-form-urlencoded
Unirest.post("http://localhost")
.field("fruit", "apple")
.field("droid", "R2D2")
.asEmpty();
// This will post a simple name-value pair body the same as a HTML form. This looks like
// `fruit=apple&droid=R2D2'
File Uploads
You can also post binary data in a form. Like a file.
The Content-Type
for this type of request is defaulted to multipart/form-data
Unirest.post("http://localhost")
.field("upload", new File("/MyFile.zip"))
.asEmpty();
For large files you may want to use a InputStream. Pass it a file name if you want one. We are using a FileInputStream here but it can actually be any kind of InputStream.
InputStream file = new FileInputStream(new File("/MyFile.zip"));
Unirest.post("http://localhost")
.field("upload", file, "MyFile.zip")
.asEmpty();
Upload Progress Monitoring
If you are uploading large files you might want to provide some time of progress bar to a user. You can monitor this progress by providing a ProgresMonitor.
Unirest.post("http://localhost")
.field("upload", new File("/MyFile.zip"))
.uploadMonitor((field, fileName, bytesWritten, totalBytes) -> {
updateProgressBarWithBytesLeft(totalBytes - bytesWritten);
})
.asEmpty();
Asynchronous Requests
Sometimes, well most of the time, you want your application to be asynchronous and not block, Unirest supports this in Java using anonymous callbacks, or direct method placement. All request types also support async versions.
CompletableFuture<HttpResponse<JsonNode>> future = Unirest.post("http://localhost/post")
.header("accept", "application/json")
.field("param1", "value1")
.field("param2", "value2")
.asJsonAsync(response -> {
int code = response.getStatus();
JsonNode body = response.getBody();
});
Paged Requests
Sometimes services offer paged requests. How this is done is not standardized but Unirest proves a mechanism to follow pages until all have been consumed. You must provide two functions for extracting the next page. The first is to get the HttpResponse in the format you want, the other is to extract the next
link from the response. The result is a PagedList
of HttpResponse<T>
. The paged list has some handy methods for dealing with the results. Here we are getting a paged list of Dogs where the next
link is in the headers.
PagedList<Doggos> result = Unirest.get("https://somewhere/dogs")
.asPaged(
r -> r.asObject(Doggos.class),
r -> r.getHeaders().getFirst("nextPage")
);
Client Certificates
In case you need to use a custom client certificate to call a service you can provide unirest with a custom keystore. You may either pass a KeyStore object or a path to a valid PKCS#12 keystore file.
Unirest.config()
.clientCertificateStore("/path/mykeystore.p12", "password1!");
Unirest.get("https://some.custom.secured.place.com")
.asString();
Proxies
Sometimes you need to tunnel through a proxy. Unirest can be configured to do this. Note that authenticated proxies cannot be configured on a per-request basis unless you want to build it into the URL itself.
// Configure with authentication:
Unirest.config().proxy("proxy.com", 7777, "username", "password1!");
// or without
Unirest.config().proxy("proxy.com", 7777);
// or pass it in the request. This will override any proxy done in the config
// currently only unauthenticated proxies work
Unirest.get(MockServer.GET)
.proxy("proxy.com", 7777)
.asString();
Responses
Unirest makes the actual request the moment you invoke of it’s as[type]
method. These methods also inform Unirest what type to map the response to. Options are Empty
, String
, File
, Object
, byte
and Json
.
The response returns as a HttpResponse<T>
where the HttpResponse
object has all of the common response data like status and headers. The Body (if present) can be accessed via the desired type with the .getBody()
method.
Empty Responses
If you aren’t expecting a body back, asEmpty
is the easiest choice. You will still get back response information like status and headers.
HttpResponse response = Unirest.delete("http://localhost").asEmpty()
String Responses
The next easiest response type is String. You can do whatever you want with it after that.
String body = Unirest.get("http://localhost")
.asString()
.getBody();
Object Mapped Responses
Most of the time when consuming RESTful services you probably want to map the response into an object.
For this you need to provide the Unirest configuration with a implementation of ObjectMapper
(see Object Mappers for details.).
If the response is JSON you are in luck and Unirest comes with a basic JsonObjectMapper
basic on Google GSON
Before an asObject(Class)
it is necessary to provide a custom implementation of the ObjectMapper
interface (if you do not wish to use the default mapper). This should be done only the first time, as the instance of the ObjectMapper will be shared globally.
Unirest offers a few plug-ins implementing popular object mappers like Jackson and Gson. See mvn central for details.
For example,
// Response to Object
Book book = Unirest.get("http://localhost/books/1")
.asObject(Book.class)
.getBody();
// Generic types can be resolved by using a GenericType subclass to avoid erasure
List<Book> books = Unirest.get("http://localhost/books/")
.asObject(new GenericType<List<Book>>(){})
.getBody();
Author author = Unirest.get("http://localhost/books/{id}/author")
.routeParam("id", bookObject.getId())
.asObject(Author.class)
.getBody();
Errors in Object or JSON parsing
You can’t always get what you want. And sometimes results you get from web services will not map into what you expect them to.
When this happens with a asObject
or asJson
request the resulting body will be null, but the response object will contain a ParsingException that allows you to get the error and the original body for inspection.
UnirestParsingException ex = response.getParsingError().get();
ex.getOriginalBody(); // Has the original body as a string.
ex.getMessage(); // Will have the parsing exception.
ex.getCause(); // of course will have the original parsing exception itself.
Mapping Error Objects
Sometimes with REST API’s the service will return a error object that can be parsed. You can optionally map this into an POJO like
HttpResponse<Book> book = Unirest.get("http://localhost/books/{id}")
.asObject(Book.class);
// This will be null if there wasn't an error
Error er = book.mapError(Error.class);
// You can also take advantage of this inside of the ifFailure method
Unirest.get("http://localhost/books/{id}")
.asObject(Book.class)
.ifFailure(Error.class, r -> {
Error e = r.getBody();
});
Mapping one body type to another without an object mapper
If you don’t want to provide a full ObjectMapper implementation you may use a simple function to map the response
int body = Unirest.get("http://httpbin/count")
.asString()
.mapBody(Integer::valueOf);
File Responses
Sometimes you just want to download a file, or maybe capture the response body into a file. Unirest can do both. Just tell Unirest where you want to put the file.
File result = Unirest.get("http://some.file.location/file.zip")
.asFile("/disk/location/file.zip")
.getBody();
Download Progress Monitoring
If you are uploading large files you might want to provide some time of progress bar to a user. You can monitor this progress by providing a ProgresMonitor.
Unirest.get("http://localhost")
.downLoadMonitor((b, fileName, bytesWritten, totalBytes) -> {
updateProgressBarWithBytesLeft(totalBytes - bytesWritten);
})
.asFile("/disk/location/file.zip");
JSON responses
Unirest offers a lightweight JSON response type when you don’t need a full Object Mapper.
String result = Unirest.get("http://some.json.com")
.asJson()
.getBody()
.getObject()
.getJSONObject("car")
.getJSONArray("wheels")
.get(0)
Large Responses
Some response methods (asString
, asJson
) read the entire
response stream into memory. In order to read the original stream and handle large responses you
can use several functional methods like:
Map r = Unirest.get(MockServer.GET)
.queryString("firstname", "Gary")
.asObject(i -> new Gson().fromJson(i.getContentReader(), HashMap.class))
.getBody();
or consumers:
Unirest.get(MockServer.GET)
.thenConsumeAsync(r -> {
// something like writing a file to disk
});
Error Handling
the HttpResponse object has a few handler methods that can be chained to deal with success and failure:
ifSuccess(Consumer<HttpResponse<T>> response)
will be called if the response was a 200-series response and any body processing (likejson
orObject
was successful.ifFailure(Consumer<HttpResponse> response
will be called if the status was 400+ or body processing failed.
Putting them together might look like this:
Unirest.get("http://somewhere")
.asJson()
.ifSuccess(response -> someSuccessMethod(response))
.ifFailure(response -> {
log.error("Oh No! Status" + response.getStatus());
response.getParsingError().ifPresent(e -> {
log.error("Parsing Exception: ", e);
log.error("Original body: " + e.getOriginalBody());
});
});
Caching
Unirest offers a simple im memory response caching mechanism with a few options for entry expiration. This can be either be enabled with defaults, with expiration options or consumers may supply a custom cache backed by the cache of their choice. It is reccomended that in high load systems consumers back the cache with a dedicated cache implementation like EHCache or Guava.
Basic cache:
Unirest.config().cacheResponses(true);
//These 1st response will be cached in this case:
Unirest.get("https://somwhere").asString();
Unirest.get("https://somwhere").asString();
Advanced Options:
You can use a builder to customize eviction rules:
Unirest.config().cacheResponses(builder()
.depth(5) // Depth is the max number of entries cached
.maxAge(5, TimeUnit.MINUTES)); // Max age is how long the entry will be kept.
Custom Caches
You can also supply a custom cache by implementing the Cache Interface
public static void main(String[] args){
Unirest.config().cacheResponses(Cache.builder().backingCache(new GuavaCache()));
}
// Example backing cache using Guava
public static class GuavaCache implements Cache {
com.google.common.cache.Cache<Key, HttpResponse> regular = CacheBuilder.newBuilder().build();
com.google.common.cache.Cache<Key, CompletableFuture> async = CacheBuilder.newBuilder().build();
@Override
public <T> HttpResponse get(Key key, Supplier<HttpResponse<T>> fetcher) {
try {
return regular.get(key, fetcher::get);
} catch (ExecutionException e) {
throw new RuntimeException(e);
}
}
@Override
public <T> CompletableFuture getAsync(Key key, Supplier<CompletableFuture<HttpResponse<T>>> fetcher) {
try {
return async.get(key, fetcher::get);
} catch (ExecutionException e) {
throw new RuntimeException(e);
}
}
}
Configuration
Previous versions of unirest had configuration split across several different places. Sometimes it was done on Unirest
, sometimes it was done on Option
, sometimes it was somewhere else.
All configuration is now done through Unirest.config()
Unirest.config()
.connectTimeout(1000)
.proxy(new Proxy("https://proxy"))
.setDefaultHeader("Accept", "application/json")
.followRedirects(false)
.enableCookieManagement(false)
.addInterceptor(new MyCustomInterceptor());
Changing Unirest’s config should ideally be done once, or rarely. Once Unirest has been activated configuration options that are involved in creating the client cannot be changed without an explicit shutdown or reset.
Config Options
Builder Method | Impact | Default |
---|---|---|
connectTimeout(int) |
Sets the connection timeout for all requests in millis | 10000 |
proxy(proxy) |
Sets a proxy object for negotiating proxy servers. Can include auth credentials | |
setDefaultHeader(String, String) |
Sets a default header. Will overwrite if it exists | |
setDefaultHeader(String, Supplier<String>) |
Sets a default header by supplier. Good for setting trace tokens for microservice architectures. Will overwrite if it exists | |
addDefaultHeader(String, String) |
Adds a default header. Multiple for the same name can exist | |
addDefaultHeader(String, Supplier<String>) |
Add a default header by supplier. Good for setting trace tokens for microservice architectures. | |
setDefaultBasicAuth(String, String) |
Add a default Basic Auth Header | |
followRedirects(boolean) |
toggle following redirects | true |
enableCookieManagement(boolean) |
toggle accepting and storing cookies | true |
cookieSpec(String) |
set a cookie policy. Acceptable values: ‘default’ (same as Netscape), ‘netscape’, ‘ignoreCookies’, ‘standard’ (RFC 6265 interoprability profile) , ‘standard-strict’ (RFC 6265 strict profile) | default |
automaticRetries(boolean) |
toggle disabling automatic retries (up to 4 times) for socket timeouts | true |
verifySsl(boolean) |
toggle enforcing SSL | true |
addShutdownHook(boolean) |
toggle to add the clients to the system shutdown hooks automatically | false |
clientCertificateStore(String,String) |
Add a PKCS12 KeyStore by path for doing client certificates | |
clientCertificateStore(KeyStore,String) |
Add a PKCS12 KeyStore for doing client certificates | |
connectionTTL(long,TimeUnit) |
Total time to live (TTL) defines maximum life span of persistent connections regardless of their expiration setting. No persistent connection will be re-used past its TTL value. | -1 |
connectionTTL(Duration) |
Add total time to live (TTL) by Duration. Good for moderns Java APIs. | -1 |
errorHandler(Consumer<HttpResponse<?>> consumer) |
Set a global error handler that will be invoked for any status > 400 or a parsing error | |
interceptor(Interceptor value) |
Set a global Interceptor handler that will be invoked before and after each request | |
defaultBaseUrl(String value) |
Set a default base URL to be used for all requests that do not already contain a scheme |
Global Interceptor
You can set a global interceptor for your configuration. This is invoked before and after each request. This can be useful for logging or injecting common attributes.
See Interceptor.java for details.
Multiple Configurations
As usual, Unirest maintains a primary single instance. Sometimes you might want different configurations for different systems. You might also want an instance rather than a static context for testing purposes.
// this returns the same instance used by Unirest.get("http://somewhere/")
UnirestInstance unirest = Unirest.primaryInstance();
// It can be configured and used just like the static context
unirest.config().connectTimeout(5000);
String result = unirest.get("http://foo").asString().getBody();
// You can also get a whole new instance
UnirestInstance unirest = Unirest.spawnInstance();
WARNING! If you get a new instance of unirest YOU are responsible for shutting it down when the JVM shuts down. It is not tracked or shut down by Unirest.shutDown();
Object Mappers
Unirest offers a few different Object Mapper’s based on popular JSON libraries (Jackson and GSON).
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-modules-jackson</artifactId>
</dependency>
<dependency>
<groupId>com.konghq</groupId>
<artifactId>unirest-modules-gson</artifactId>
</dependency>
If you have some other need you can supply your own Object mapper by implementing the ObjectMapper
interface. It has only a few methods
Metrics
Unirest has hooks for collecting metrics on your runtime code. This is a simple and lightweight framework that marks two events:
- The moment just before the actual request is made
- The moment just after the actual request is made
Context information like method and request path are given to you so that you can collect based on whatever your needs are. In its simplest form it might look like this:
Unirest.config().instrumentWith(requestSummary -> {
long startNanos = System.nanoTime();
return (responseSummary,exception) -> logger.info("path: {} status: {} time: {}",
requestSummary.getRawPath(),
responseSummary.getStatus(),
System.nanoTime() - startNanos);
});
By providing more feature rich UniMetric instances you could easily calculate averages per route, uptime, or other fun facts.
Shutting Down
Unirest starts a background event loop and your Java application won’t be able to exit until you manually shutdown all the threads by invoking:
Unirest.shutdown();
Once shutdown, using Unirest again will re-init the system