[WIP] Convert to async/await

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.2
+// swift-tools-version:5.5
 import PackageDescription
 
 let package = Package(

Sources/wkhtmltopdf/Document+Generate.swift

@@ -2,51 +2,56 @@ import Foundation
 import NIO
 
 extension Document {
+    @available(macOS 12.0.0, *)
+    public func generatePDF(on threadPool: NIOThreadPool, eventLoop: EventLoop) async throws -> Data {
+        try await withCheckedThrowingContinuation { continuation in
+            _ = threadPool.runIfActive(eventLoop: eventLoop) {
+                let fileManager = FileManager.default
 
-    public func generatePDF(on threadPool: NIOThreadPool, eventLoop: EventLoop) -> EventLoopFuture<Data> {
-        return threadPool.runIfActive(eventLoop: eventLoop) {
-            let fileManager = FileManager.default
+                // Create the temp folder if it doesn't already exist
+                let workDir = "/tmp/vapor-wkhtmltopdf"
+                try fileManager.createDirectory(atPath: workDir, withIntermediateDirectories: true)
 
-            // Create the temp folder if it doesn't already exist
-            let workDir = "/tmp/vapor-wkhtmltopdf"
-            try fileManager.createDirectory(atPath: workDir, withIntermediateDirectories: true)
+                // Save input pages to temp files, and build up args to wkhtmltopdf
+                var wkArgs: [String] = [
+                    "--zoom", self.zoom,
+                    "--quiet",
+                    "-s", self.paperSize,
+                    "-T", "\(self.topMargin)mm",
+                    "-R", "\(self.rightMargin)mm",
+                    "-B", "\(self.bottomMargin)mm",
+                    "-L", "\(self.leftMargin)mm",
+                ]
+
+                wkArgs += self.wkArgs
+
+                let pageFiles: [String] = try self.pages.map { page in
+                    let name = UUID().uuidString + ".html"
+                    let filename = "\(workDir)/\(name)"
+                    try page.content.write(to: URL(fileURLWithPath: filename))
+                    return filename
+                }
+                defer {
+                    try? pageFiles.forEach(fileManager.removeItem)
+                }
 
-            // Save input pages to temp files, and build up args to wkhtmltopdf
-            var wkArgs: [String] = [
-                "--zoom", self.zoom,
-                "--quiet",
-                "-s", self.paperSize,
-                "-T", "\(self.topMargin)mm",
-                "-R", "\(self.rightMargin)mm",
-                "-B", "\(self.bottomMargin)mm",
-                "-L", "\(self.leftMargin)mm",
-            ]
-
-            wkArgs += self.wkArgs
-
-            let pageFiles: [String] = try self.pages.map { page in
-                let name = UUID().uuidString + ".html"
-                let filename = "\(workDir)/\(name)"
-                try page.content.write(to: URL(fileURLWithPath: filename))
-                return filename
+                wkArgs += pageFiles
+
+                // Call wkhtmltopdf and retrieve the result data
+                let wk = Process()
+                let stdout = Pipe()
+                wk.launchPath = self.launchPath
+                wk.arguments = wkArgs
+                wk.arguments?.append("-") // output to stdout
+                wk.standardOutput = stdout
+                wk.launch()
+
+                let pdf = stdout.fileHandleForReading.readDataToEndOfFile()
+                continuation.resume(returning: pdf)
+            }.flatMapErrorThrowing { err in
+                continuation.resume(throwing: err)
+                return
             }
-            defer {
-                try? pageFiles.forEach(fileManager.removeItem)
-            }
-
-            wkArgs += pageFiles
-
-            // Call wkhtmltopdf and retrieve the result data
-            let wk = Process()
-            let stdout = Pipe()
-            wk.launchPath = self.launchPath
-            wk.arguments = wkArgs
-            wk.arguments?.append("-") // output to stdout
-            wk.standardOutput = stdout
-            wk.launch()
-
-            let pdf = stdout.fileHandleForReading.readDataToEndOfFile()
-            return pdf
         }
     }
 }

Tests/wkhtmltopdfTests/wkhtmltopdfTests.swift

@@ -2,6 +2,7 @@ import XCTest
 import NIO
 @testable import wkhtmltopdf
 
+@available(macOS 12.0.0, *)
 class wkhtmltopdfTests: XCTestCase {
 
     var group: EventLoopGroup!
@@ -18,15 +19,15 @@ class wkhtmltopdfTests: XCTestCase {
         XCTAssertNoThrow(try group.syncShutdownGracefully())
     }
 
-    func testStringPDF() throws {
+    func testStringPDF() async throws {
         let eventLoop = group.next()
 
         let document = Document(margins: 15)
         let page1 = Page("<p>Page from direct HTML</p>")
         document.pages = [page1]
         let threadPool = NIOThreadPool(numberOfThreads: 1)
         threadPool.start()
-        let data = try document.generatePDF(on: threadPool, eventLoop: eventLoop).wait()
+        let data = try await document.generatePDF(on: threadPool, eventLoop: eventLoop)
         try threadPool.syncShutdownGracefully()
         // Cop-out test, just ensuring that the returned data is something
         XCTAssert(data.count > 50)