• Kotlin - ​

  

  ​​

• URL encoded style for GET and DELETE request

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  Fuel.get("https://httpbin.org/get", listOf("foo" to "foo", "bar" to "bar"))

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  .url

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  // https://httpbin.org/get?foo=foo&bar=bar

  Copied!

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  Fuel.delete("https://httpbin.org/delete", listOf("foo" to "foo", "bar" to "bar"))

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  .url

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  // https://httpbin.org/delete?foo=foo&bar=bar

  Copied!
• Support x-www-form-urlencoded for PUT, POST and PATCH

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  Fuel.post("https://httpbin.org/post", listOf("foo" to "foo", "bar" to "bar"))

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  .also { println(it.url) }

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  .also { println(String(it.body().toByteArray())) }

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  ​

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  // https://httpbin.org/post

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  // "foo=foo&bar=bar"

  Copied!

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  Fuel.put("https://httpbin.org/put", listOf("foo" to "foo", "bar" to "bar"))

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  .also { println(it.url) }

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  .also { println(String(it.body().toByteArray())) }

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  ​

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  // https://httpbin.org/put

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  // "foo=foo&bar=bar"

  Copied!

• a list is encoded as key[]=value1&key[]=value2&...
• an array is encoded as key[]=value1&key[]=value2&...
• an empty string value is encoded as key
• a null value is removed

• POST
• PUT
• PATCH (actually a POST, as noted above)
• DELETE

When you call .authentication(), a few extra functions are available. If you call a regular function (e.g. .header()) the extra functions are no longer available, but you can safely call .authentication() again without losing any previous calls.

• Basic authentication

• Bearer authentication

• Any authentication using a header

When you call .upload(), a few extra functions are available. If you call a regular function (e.g. .header()) the extra functions are no longer available, but you can safely call .upload() again without losing any previous calls.

• The ResponseResultOf<U> type is a Triple of the Request, Response and a Result<U, FuelError>
• The ResponseOf<U> type is a Triple of the Request, Response and a U; errors are thrown
• The Result<U, FuelError> type is a non-throwing wrapper around U
• The U type doesn't wrap anything; errors are thrown

• You can call [fold] and define a tranformation function for both cases that results in the same return type,
• [destructure] as (data, error) = result because it is just a data class or
• use when checking whether it is Result.Success or Result.Failure

When you call .download(), a few extra functions are available. If you call a regular function (e.g. .header()) the extra functions are no longer available, but you can safely call .download() again without losing any previous calls.

• The OutputStream is always closed after the body has been written. Make sure you wrap whatever functionality you need on top of the stream and don't rely on the stream to remain open.
• The () -> InputStream replaces the body after the current body has been written to the OutputStream. It is used to make sure you can also retrieve the body via the response / await method results. If you don't want the body to be readable after downloading it, you have to do two things:

  • use an EmptyDeserializer with await(deserializer) or one of the response(deserializer) variants
  • provide an InputStream callback that throws or returns an empty InputStream.

• baseHeaders is to manage common HTTP header pairs in format of Map<String, String>.

  • The base headers are only applied if the request does not have those headers set.

• Headers can be added to a request via various methods including

• By default, all subsequent calls overwrite earlier calls, but you may use the appendHeader variant to append values to existing values.

  • In earlier versions (1.x.y), a mapOf overwrote, and varargs pair did not, but this was confusing. In 2.0, this issue has been fixed and improved so it works as expected.

• Some of the HTTP headers are defined under Headers.Companion and can be used instead of literal strings. This is an encouraged way to configure your header in 2.x.y.

• Fuel provides built-in support for response deserialization. Here is how one might want to use Fuel together with Gson​

• There are 4 methods to support response deserialization depending on your needs (also depending on JSON parsing library of your choice), and you are required to implement only one of them.

• Another example may be parsing a website that is not UTF-8. By default, Fuel serializes text as UTF-8, we need to define our deserializer as such

• Use singleton FuelManager.instance to manage global configurations.
• Create separate managers using FuelManager()
• basePath is used to manage common root path. Great usage is for your static API endpoint.

• baseParams is used to manage common key=value query param, which will be automatically included in all of your subsequent requests in format of Parameters (Any is converted to String by toString() method)

• client is a raw HTTP client driver. Generally, it is responsible to make Request into Response. Default is HttpClient which is a thin wrapper over java.net.HttpUrlConnection. You could use any httpClient of your choice by conforming to client protocol, and set back to FuelManager.instance to kick off the effect.
• keyStore is configurable by user. By default it is null.
• socketFactory can be supplied by user. If keyStore is not null, socketFactory will be derived from it.
• hostnameVerifier is configurable by user. By default, it uses HttpsURLConnection.getDefaultHostnameVerifier().
• requestInterceptors responseInterceptors is a side-effect to add to Request and/or Response objects.

  • For example, one might wanna print cUrlString style for every request that hits server in DEBUG mode.

• Another example is that you might wanna add data into your Database, you can achieve that with providing responseInterceptors such as