Discover ways to implement a primary HTML file add type utilizing the Leaf template engine and Vapor, all written in Swift after all.
Vapor
Constructing a file add type
Let’s begin with a primary Vapor challenge, we’ll use Leaf (the Tau launch) for rendering our HTML recordsdata. It is best to observe that Tau was an experimental launch, the modifications have been reverted from the ultimate 4.0.0 Leaf launch, however you’ll be able to nonetheless use Tau for those who pin the precise model in your manifest file. Tau will likely be printed afterward in a standalone repository… 🤫
import PackageDescription
let package deal = Bundle(
title: "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(title: "Run", dependencies: [.target(name: "App")]),
.testTarget(title: "AppTests", dependencies: [
.target(name: "App"),
.product(name: "XCTVapor", package: "vapor"),
])
]
)
Now for those who open the challenge with Xcode, remember to setup a customized working listing first, as a result of we’ll create templates and Leaf will search for these view recordsdata beneath 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 title="viewport" content material="width=device-width, initial-scale=1">
<title>File add instance</title>
</head>
<physique>
<h1>File add instance</h1>
<type motion="/add" methodology="put up" enctype="multipart/form-data">
<enter kind="file" title="file"><br><br>
<enter kind="submit" worth="Submit">
</type>
</physique>
</html>
As you’ll be able to see, it is a typical file add type, if you wish to add recordsdata utilizing the browser you at all times have to make use of the multipart/form-data encryption kind. The browser will pack each discipline within the type (together with the file knowledge with the unique file title 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 type 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 foremost web page and we’re going to put together our add path as effectively, however we are going to 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.put up("add") { req in
"Add file..."
}
}
You may 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 truly add the file, however at the least we’re ready to write down our server aspect Swift code to course of the incoming type knowledge. ⬆️
File add handler in Vapor
Now that we now have a working uploader type we should always parse the incoming knowledge, get the contents of the file and place it beneath our Public listing. You may truly transfer the file wherever in your server, however for this instance we’re going to use the Public listing so we will merely take a look at if everthing works through the use of the FileMiddleware. If you do not know, the file middleware serves the whole lot (publicly obtainable) that’s positioned inside your Public folder. Let’s code.
app.put up("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 can comprise our file knowledge. There’s a File kind in Vapor that helps us decoding multipart file add types. We are able to use the content material of the request and decode this kind. We gave the file title to the file enter type beforehand in our leaf template, however after all you’ll be able to change it, however for those who achieve this you additionally must align the property title contained in the Enter struct.
After we now have an enter (please observe that we do not validate the submitted request but) we will begin importing our file. We ask for the placement of the general public listing, we append the incoming file title (to maintain the unique title, however you’ll be able to generate a brand new title 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 will likely be extra performant if we use this as a substitute of the common FileManager from the Basis framework. After we opened the file, we write the file knowledge (which is a ByteBuffer object, dangerous naming…) and at last we shut the opened file handler and return the uploaded file title as a future string. If you have not heard about futures and guarantees it is best to examine them, as a result of they’re in all places on the server aspect Swift world. Cannot anticipate 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 title="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 examine 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 put up add handler methodology we’re going to add a date prefix to the uploaded file so we will add a number of recordsdata even with the identical title.
app.put up("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"].comprises(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),
])
}
}
}
When you run this instance it is best to have the ability 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 can even add a number of recordsdata without delay for those who add the a number of attribute to the HTML file enter discipline and use the recordsdata[] worth as title.
<enter kind="file" title="recordsdata[]" a number of><br><br>
To help this we now have to change our add methodology, don’t fret it isn’t that difficult because it appears at first sight. 😜
app.put up("add") { req -> EventLoopFuture<View> in
struct Enter: Content material {
var recordsdata: [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.recordsdata
.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"].comprises(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 { recordsdata in
req.leaf.render(template: "consequence", context: [
"files": .array(files.map(.leafData))
])
}
}
The trick is that we now have to parse the enter as an array of recordsdata and switch each attainable add right into a future add operation. We are able to filter the add candidates by readable byte measurement, then we map the recordsdata into futures and return an UploadedFile consequence with the right file URL and is picture flag. This construction is a LeafDataRepresentable object, as a result of we wish 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 title="viewport" content material="width=device-width, initial-scale=1">
<title>Information uploaded</title>
</head>
<physique>
<h1>Information uploaded</h1>
#for(file in recordsdata):
#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 recordsdata</a>
</physique>
</html>
Properly, I do know it is a useless easy implementation, but it surely’s nice if you wish to follow or learn to implement file uploads utilizing server aspect Swift and the Vapor framework. You may also add recordsdata on to a cloud service utilizing this method, there’s a library known as Liquid, which is analogous to Fluent, however for file storages. Presently you should use Liquid to add recordsdata to the native storage or you should use an AWS S3 bucket or you’ll be able to write your individual driver utilizing LiquidKit. The API is fairly easy to make use of, after you configure the driving force you’ll be able to add recordsdata with just some strains of code.
I hope you preferred this tutorial, if in case you have any questions or concepts, please let me know.
