Learn to implement a primary HTML file add kind utilizing the Leaf template engine and Vapor, all written in Swift after all.
Vapor
Constructing a file add kind
Let’s begin with a primary Vapor venture, we’ll use Leaf (the Tau launch) for rendering our HTML information. It’s best to be aware that Tau was an experimental launch, the modifications had been reverted from the ultimate 4.0.0 Leaf launch, however you’ll be able to nonetheless use Tau if you happen to pin the precise model in your manifest file. Tau shall be printed in a while in a standalone repository… 🤫
import PackageDescription
let package deal = Package deal(
identify: "myProject",
platforms: [
.macOS(.v10_15)
],
dependencies: [
.package(url: "https://github.com/vapor/vapor", from: "4.35.0"),
.package(url: "https://github.com/vapor/leaf", .exact("4.0.0-tau.1")),
.package(url: "https://github.com/vapor/leaf-kit", .exact("1.0.0-tau.1.1")),
],
targets: [
.target(
name: "App",
dependencies: [
.product(name: "Leaf", package: "leaf"),
.product(name: "LeafKit", package: "leaf-kit"),
.product(name: "Vapor", package: "vapor"),
],
swiftSettings: [
.unsafeFlags(["-cross-module-optimization"], .when(configuration: .launch))
]
),
.goal(identify: "Run", dependencies: [.target(name: "App")]),
.testTarget(identify: "AppTests", dependencies: [
.target(name: "App"),
.product(name: "XCTVapor", package: "vapor"),
])
]
)
Now if you happen to open the venture with Xcode, do not forget to setup a customized working listing first, as a result of we’ll create templates and Leaf will search for these view information underneath the present working listing by default. We’re going to construct a quite simple index.leaf file, you’ll be able to place it into the Sources/Views listing.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta identify="viewport" content material="width=device-width, initial-scale=1">
<title>File add instance</title>
</head>
<physique>
<h1>File add instance</h1>
<kind motion="/add" technique="publish" enctype="multipart/form-data">
<enter kind="file" identify="file"><br><br>
<enter kind="submit" worth="Submit">
</kind>
</physique>
</html>
As you’ll be able to see, it is a typical file add kind, whenever you need to add information utilizing the browser you at all times have to make use of the multipart/form-data encryption kind. The browser will pack each area within the kind (together with the file knowledge with the unique file identify and a few meta information) utilizing a particular format and the server software can parse the contents of this. Happily Vapor has built-in help for simple decoding multipart kind knowledge values. We’re going to use the POST /add route to save lots of the file, let’s setup the router first so we will render our predominant web page and we’re going to put together our add path as effectively, however we’ll reply with a dummy message for now.
import Vapor
import Leaf
public func configure(_ app: Utility) throws {
app.routes.defaultMaxBodySize = "10mb"
app.middleware.use(FileMiddleware(publicDirectory: app.listing.publicDirectory))
LeafRenderer.Choice.caching = .bypass
app.views.use(.leaf)
app.get { req in
req.leaf.render(template: "index")
}
app.publish("add") { req in
"Add file..."
}
}
You’ll be able to put the snippet above into your configure.swift file then you’ll be able to attempt to construct and run your server and go to http://localhost:8080, then attempt to add any file. It will not really add the file, however at the least we’re ready to jot down our server aspect Swift code to course of the incoming kind knowledge. ⬆️
File add handler in Vapor
Now that we’ve a working uploader kind we should always parse the incoming knowledge, get the contents of the file and place it underneath our Public listing. You’ll be able to really transfer the file wherever in your server, however for this instance we’re going to use the Public listing so we will merely check if everthing works by utilizing the FileMiddleware. If you do not know, the file middleware serves every little thing (publicly obtainable) that’s situated inside your Public folder. Let’s code.
app.publish("add") { req -> EventLoopFuture<String> in
struct Enter: Content material {
var file: File
}
let enter = attempt req.content material.decode(Enter.self)
let path = app.listing.publicDirectory + enter.file.filename
return req.software.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.software.fileio.write(fileHandle: deal with,
buffer: enter.file.knowledge,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
return enter.file.filename
}
}
}
So, let me clarify what simply occurred right here. First we outline a brand new Enter kind that may include our file knowledge. There’s a File kind in Vapor that helps us decoding multipart file add kinds. We will use the content material of the request and decode this sort. We gave the file identify to the file enter kind beforehand in our leaf template, however after all you’ll be able to change it, however if you happen to achieve this you additionally should align the property identify contained in the Enter struct.
After we’ve an enter (please be aware that we do not validate the submitted request but) we will begin importing our file. We ask for the situation of the general public listing, we append the incoming file identify (to maintain the unique identify, however you’ll be able to generate a brand new identify for the uploaded file as effectively) and we use the non-blocking file I/O API to create a file handler and write the contents of the file into the disk. The fileio API is a part of SwiftNIO, which is nice as a result of it is a non-blocking API, so our server shall be extra performant if we use this as an alternative of the common FileManager from the Basis framework. After we opened the file, we write the file knowledge (which is a ByteBuffer object, unhealthy naming…) and at last we shut the opened file handler and return the uploaded file identify as a future string. If you have not heard about futures and guarantees you need to examine them, as a result of they’re in every single place on the server aspect Swift world. Cannot look forward to async / awake help, proper? 😅
We are going to improve the add consequence web page just a bit bit. Create a brand new consequence.leaf file contained in the views listing.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta identify="viewport" content material="width=device-width, initial-scale=1">
<title>File uploaded</title>
</head>
<physique>
<h1>File uploaded</h1>
#if(isImage):
<img src="#(fileUrl)" width="256px"><br><br>
#else:
<a href="#(fileUrl)" goal="_blank">Present me!</a><br><br>
#endif
<a href="/">Add new one</a>
</physique>
</html>
So we’ll test if the uploaded file has a picture extension and cross an isImage parameter to the template engine, so we will show it if we will assume that the file is a picture, in any other case we’ll render a easy hyperlink to view the file. Contained in the publish add handler technique we’re going to add a date prefix to the uploaded file so we can add a number of information even with the identical identify.
app.publish("add") { req -> EventLoopFuture<View> in
struct Enter: Content material {
var file: File
}
let enter = attempt req.content material.decode(Enter.self)
guard enter.file.knowledge.readableBytes > 0 else {
throw Abort(.badRequest)
}
let formatter = DateFormatter()
formatter.dateFormat = "y-m-d-HH-MM-SS-"
let prefix = formatter.string(from: .init())
let fileName = prefix + enter.file.filename
let path = app.listing.publicDirectory + fileName
let isImage = ["png", "jpeg", "jpg", "gif"].accommodates(enter.file.extension?.lowercased())
return req.software.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.software.fileio.write(fileHandle: deal with,
buffer: enter.file.knowledge,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
}
.flatMap {
req.leaf.render(template: "consequence", context: [
"fileUrl": .string(fileName),
"isImage": .bool(isImage),
])
}
}
}
In the event you run this instance you need to be capable to view the picture or the file straight from the consequence web page.
A number of file add utilizing Vapor
By the way in which, you may as well add a number of information without delay if you happen to add the a number of attribute to the HTML file enter area and use the information[] worth as identify.
<enter kind="file" identify="information[]" a number of><br><br>
To help this we’ve to change our add technique, don’t fret it isn’t that difficult because it seems at first sight. 😜
app.publish("add") { req -> EventLoopFuture<View> in
struct Enter: Content material {
var information: [File]
}
let enter = attempt req.content material.decode(Enter.self)
let formatter = DateFormatter()
formatter.dateFormat = "y-m-d-HH-MM-SS-"
let prefix = formatter.string(from: .init())
struct UploadedFile: LeafDataRepresentable {
let url: String
let isImage: Bool
var leafData: LeafData {
.dictionary([
"url": url,
"isImage": isImage,
])
}
}
let uploadFutures = enter.information
.filter { $0.knowledge.readableBytes > 0 }
.map { file -> EventLoopFuture<UploadedFile> in
let fileName = prefix + file.filename
let path = app.listing.publicDirectory + fileName
let isImage = ["png", "jpeg", "jpg", "gif"].accommodates(file.extension?.lowercased())
return req.software.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.software.fileio.write(fileHandle: deal with,
buffer: file.knowledge,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
return UploadedFile(url: fileName, isImage: isImage)
}
}
}
return req.eventLoop.flatten(uploadFutures).flatMap { information in
req.leaf.render(template: "consequence", context: [
"files": .array(files.map(.leafData))
])
}
}
The trick is that we’ve to parse the enter as an array of information and switch each potential add right into a future add operation. We will filter the add candidates by readable byte measurement, then we map the information into futures and return an UploadedFile consequence with the correct file URL and is picture flag. This construction is a LeafDataRepresentable object, as a result of we need to cross it as a context variable to our consequence template. We even have to alter that view as soon as once more.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta identify="viewport" content material="width=device-width, initial-scale=1">
<title>Recordsdata uploaded</title>
</head>
<physique>
<h1>Recordsdata uploaded</h1>
#for(file in information):
#if(file.isImage):
<img src="#(file.url)" width="256px"><br><br>
#else:
<a href="#(file.url)" goal="_blank">#(file.url)</a><br><br>
#endif
#endfor
<a href="/">Add new information</a>
</physique>
</html>
Nicely, I do know it is a lifeless easy implementation, however it’s nice if you wish to follow or learn to implement file uploads utilizing server aspect Swift and the Vapor framework. It’s also possible to add information on to a cloud service utilizing this system, there’s a library known as Liquid, which is analogous to Fluent, however for file storages. At present you should use Liquid to add information to the native storage or you should use an AWS S3 bucket or you’ll be able to write your personal driver utilizing LiquidKit. The API is fairly easy to make use of, after you configure the motive force you’ll be able to add information with only a few strains of code.
I hope you preferred this tutorial, when you’ve got any questions or concepts, please let me know.
