S3SignerAWS

Generates V4 authorization headers and pre-signed URLs for authenticating AWS S3 REST API calls

Check out VaporS3Signer if your using Vapor.

Features

• Pure Swift
• All required headers generated automatically
• V4 Authorization header
• V4 pre-signed URL
• Support DELETE/GET/HEAD/PUT/POST
• Single chunk uploads
• Multiple chunk uploads

Table of Contents

• Integration
• Usage
  • V4 Authorization Header
  • V4 Pre-Signed URL

Integration

Swift Package Manager

To install with swift package manager, add the package to your Package.swift file:

Import PackageDescription

  let package = Package(
    name: "Your_Project_Name",
    targets: [],
    dependencies: [
        .package(url: "https://github.com/JustinM1/S3SignerAWS.git", from: "4.0.0")
    ]
  )  

Usage

NOTE ABOUT PAYLOAD:

Requests can either have a signed payload or an unsigned payload.

• If you know the request will not have a payload, set the Payload property to none. This tells s3 that the signature was created with no payload intended

• If you are not sure what the exact payload will be, set payload property to unsigned. This tells s3 when you made the signature, there was a possibility of a payload but you weren’t sure what specific object will be uploaded.

• Payload enum:

  public enum Payload {
    case data(Data)
    case none
    case unsigned
  }

  To begin working with the S3SignerAWS class, initialize an instance similar to example shown below:

let s3Signer = S3SignerAWS(accessKey: "YOUR_AWS_PUBLIC_KEY", secretKey: "YOUR_AWS_SECRET_KEY", region: .usStandard_usEast1)  

NOTE - Hardcoding Secret Keys on client is not recommended for security reasons.

V4 Authorization Header

For both V4 Authorization Header and Pre-Signed URL, you can add additional headers as needed for your specific use case.

GET

do {
  guard let url = URL(string: "https://s3.amazonaws.com/bucketName/testUploadImage.png") else { throw someError }
  let headers = try s3Signer.authHeaderV4(httpMethod: .get, urlString: url.absoluteString, headers: [:], payload: .none)          
  var request = URLRequest(url: url)
  request.httpMethod = HTTPMethod.get.rawValue
  headers.forEach { request.setValue($0.key, forHTTPHeaderField: $0.value) }
      // make network request
    } catch {
      //handle error
    }
  }

PUT

do {
  let bytesObject = try someDataObject.makeBytes()
  guard let url = URL(string: "https://s3.amazonaws.com/bucketName/testUploadImage.png") else { throw someError }
  let headers = try s3Signer.authHeadersV4(httpMethod: .put, urlString: url.absoluteString, headers: [:], payload: .bytes(bytesObject))
  var request = URLRequest(url: url)
  request.httpMethod = HTTPMethod.put.rawValue
  request.httpBody = Data(bytes: bytesObject)
  headers.forEach { request.setValue($0.key, forHTTPHeaderField: $0.value) }
      // make network request
    } catch {
    //handle error
    }
  }

DELETE

do {
  guard let url = URL(string: "https://s3.amazonaws.com/bucketName/testUploadImage.png") else { throw someError }
  let headers = try s3Signer.authHeadersV4(httpMethod: .delete, urlString: url.absoluteString, headers: [:], payload: .none)
  var request = URLRequest(url: url)
  request.httpMethod = HTTPMethod.delete.rawValue
  headers.forEach { request.setValue($0.key, forHTTPHeaderField: $0.value) }
      // make network request
    } catch {
      //handle error
    }
  }

V4 Pre-Signed URL

Similar to the ease of generating authentication headers, to generate a pre-signed url:

let presignedURL = signer.presignedURLV4(httpMethod: HTTPMethod, urlString: String, expiration: TimeFromNow, headers: [String: String]) -> String