URLQueryEncoder

A customizable Swift Encoder that encodes instances of data types as URL query items. Supports all OpenAPI serialization options.

Examples

Encoding Primitives

let encoder = URLQueryEncoder()
encoder.encode(id, forKey: "id")

print(encoder.queryItems)
// [URLQueryItem(name: "id", value: "5")]

By default, optional values are not encoded.

var id: Int?
let encoder = URLQueryEncoder()
encoder.encode(id, forKey: "id")

print(encoder.queryItems)
// []

Encoding Arrays

let ids = [3, 4, 5]
let encoder = URLQueryEncoder()
encoder.encode(ids, forKey: "id")

// Query: "id=3&id=4&id=5"

With an explode option disabled:

let ids = [3, 4, 5]
let encoder = URLQueryEncoder()
encoder.encode(ids, forKey: "id", explode: false)

// Query: "id=3,4,5"

With an explode option disabled and a custom delimiter:

let ids = [3, 4, 5]
let encoder = URLQueryEncoder()
encoder.encode(ids, forKey: "id", explode: false, delimeter: "|")

// Query: "id=3|4|5"

Encoding Objects

let user = User(role: "admin", name: "kean")

let encoder = URLQueryEncoder()
encoder.encode(user, forKey: "id")

// Query: "role=admin&name=kean"

With an explode option disabled:

let user = User(role: "admin", name: "kean")

let encoder = URLQueryEncoder()
encoder.encode(user, forKey: "id", explode: false)

// Query: "id=role,admin,name,kean"

As a "deep" object:

let user = User(role: "admin", name: "kean")

let encoder = URLQueryEncoder()
encoder.encode(user, forKey: "id", isDeepObject: true)

// Query: "id[role]=admin&id[name]=kean")"

If you are encoding a request body using URL-form encoding, you can use a convenience URLQueryEncoder.encode(_:) method.

Encoding Options

There are two ways to change the encoding options. You can set them directly on URLQueryEncoder instance.

let encoder = URLQueryEncoder()
encoder.explode = false
encoder.isDeepObject = true
encoder.delimiter = "|"
encoder.dateEncodingStrategy = .millisecondsSince1970

Or pass options in each individual encode call.

let user = User(role: "admin", name: "kean")
let ids = [3, 4, 5]

let encoder = URLQueryEncoder()
encoder.encode(ids, forKey: "ids", explode: false)
encoder.encode(ids, forKey: "ids2", explode: true)
encoder.encode(user, forKey: "user", isDeepObject: true)
encoder.encode(2, forKey: "id")

// Query: "ids=3,4,5&ids2=3&ids2=4&ids2=5&user[role]=admin&user[name]=kean&id=2"

The reason it's designed this way is that in OpenAPI each parameter can come with different serialization options.

Accessing Results

You can access the encoding results at any time, and they come in different forms:

public final class URLQueryEncoder {
    // Encoded query items.
    public var queryItems: [URLQueryItem]
    // Encoded query items as name-value pairs.
    public var items: [(String, String?)]
    // The encoded query items as a URL query subcomponent.
    public var query: String?
    // The encoded query items as a URL query subcomponent with percent-encoded values.
    public var percentEncodedQuery: String?
}

License

URLQueryEncoder is available under the MIT license. See the LICENSE file for more info.