URLRequest+curlCommand Tests.swift

//
//  URLRequest+curlCommand Tests.swift
//
//  Created by Daniel Tartaglia on 21 Nov 2024.
//  Copyright © 2025 Daniel Tartaglia. MIT License.
//

struct curl_command_tests {
    struct first_line_tests {
        @Test func firstLineContainsGETIfMissingMethod() {
            let request = URLRequest(url: URL(string: "https://nil.dev")!)
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).first == "curl -X GET \\")
        }

        @Test func firstLineContainsMethod() {
            var request = URLRequest(url: URL(string: "https://nil.dev")!)
            request.httpMethod = "PUT"
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).first == "curl -X PUT \\")
        }

        @Test func firstLineContainsBody() {
            var request = URLRequest(url: URL(string: "https://nil.dev")!)
            request.httpBody = "FooBar".data(using: .utf8)
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).first == #"curl -X GET -d "FooBar" \"#)
        }

        @Test func quotesInBodyAreEscaped() {
            var request = URLRequest(url: URL(string: "https://nil.dev")!)
            request.httpBody = "Foo \"Bar\"".data(using: .utf8)
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).first == #"curl -X GET -d "Foo \"Bar\"" \"#)
        }
    }

    struct second_line_tests {
        @Test func secondLineContainsHeader() {
            var request = URLRequest(url: URL(string: "https://nil.dev")!)
            request.addValue("Bearer foobar", forHTTPHeaderField: "Authorization")
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).dropFirst()
                .first == #"    -H "Authorization: Bearer foobar" \"#)
        }

        @Test func quotesInHeaderAreEscaped() {
            var request = URLRequest(url: URL(string: "https://nil.dev")!)
            request.addValue("Bearer \"foo bar\"", forHTTPHeaderField: "Authorization")
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).dropFirst()
                .first == #"    -H "Authorization: Bearer \"foo bar\"" \"#)
        }

        @Test func noHeadersMeansSecondLineContainsURL() {
            let request = URLRequest(url: URL(string: "https://nil.dev")!)
            let result = request.curlCommand()
            #expect(result.components(separatedBy: .newlines).dropFirst().first == #""https://nil.dev" -i -v"#)
        }
    }

    @Test func lastLineShowsUnknownWhenURLIsMissing() {
        var request = URLRequest(url: URL(string: "https://nil.dev")!)
        request.url = nil
        let result = request.curlCommand()
        #expect(result.components(separatedBy: .newlines).last == #""<unknown url>" -i -v"#)
    }
}

URLRequest+curlCommand.swift

//
//  URLRequest+curlCommand.swift
//
//  Created by Daniel Tartaglia on 21 Nov 2024.
//  Copyright © 2025 Daniel Tartaglia. MIT License.
//

extension URLRequest {
    /// Produce a string that can be copy & pasted into the terminal in order to check the network response.
    ///
    /// - Returns: A String representing the curl command of the request.
    func curlCommand() -> String {
        template(
            method: httpMethod ?? "GET",
            body: httpBody.flatMap { String(data: $0, encoding: .utf8)?.escapedQuotes() } ?? "",
            headerFields: allHTTPHeaderFields?.map { ($0.key, $0.value.escapedQuotes()) } ?? [],
            url: url?.absoluteString ?? "<unknown url>"
        )
    }
}

private func template(method: String, body: String, headerFields: [(key: String, value: String)], url: String) -> String
{
    #"curl -X \#(method)\#(body.isEmpty ? "" : #" -d "\#(body)""#) \\#n"#
        + headerFields.map { #"    -H "\#($0.key): \#($0.value)" "# }.joined(separator: "\\\n")
        + (headerFields.isEmpty ? "" : "\\\n")
        + #""\#(url)" -i -v"#
}

private extension String {
    func escapedQuotes() -> String {
        replacingOccurrences(of: #"""#, with: #"\""#, options: [], range: nil)
    }
}