MimeEmailParser

Developed for use in Mailio mobile iOS app

What is MimeEmailParser

MimeEmailParser is a Swift 5 library which may be used for parsing and validation of email addresses. If follows Multipurpose Internet Mail Extension (MIME), as defined in RFC 5322 for email address parsing and RFC 2047 ("Q"-encoded) for decoding Non-ASCII text. List of IETF specifications

Note that this is not the full implementation of MIME, but deals only with parsing of email addresses and decoding words as defined in RFC2047.

Supported "high level formats":

address = mailbox / group
mailbox = name-addr / addr-spec
group = display-name ":" [group-list] ";" [CFWS]

The code has been adapted from official GO source; mail package: https://golang.org/src/net/mail/message.go

Features

• Parsing single and multiple email adresses
• Validation of email addresses
• Decoding RFC2047 words

Installation

Swift Package Manager

The Swift Package Manager is a tool for automating the distribution of Swift code and is integrated into the swift compiler.

Once you have your Swift package set up, adding MimeEmailParser as a dependency is as easy as adding it to the dependencies value of your Package.swift.

dependencies: [
    .package(url: "https://github.com/igorrendulic/MimeEmailParser.git", .upToNextMajor(from: "1.0.0"))
]

Manually

If you prefer not to use Swift Package Manager, you can integrate MimeEmailParser into your project manually as an Embedded Framework

• Open up Terminal, cd into your top-level project directory, and run the following command "if" your project is not initialized as a git repository:

$ git init

• Add MimeEmailParser as a git submodule by running the following command:

$ git submodule add https://github.com/igorrendulic/MimeEmailParser.git

• Open the new MimeEmailParser folder, and drag the Package.xcworkspace into the Project Navigator of your application's Xcode project.

It should appear nested underneath your application's blue project icon. Whether it is above or below all the other Xcode groups does not matter.

• Select MimeEmailParser in the Project Navigator and verify the deployment target matches that of your application target.

• Next, select your application project in the Project Navigator (blue project icon) to navigate to the target configuration window and select the application target under the "Targets" heading in the sidebar.

• And that's it!

Using MimeEmailParser

MimeEmailParser returns a single or array of Address objects:

public struct Address {
    let Name:String?
    let Address: String
}

Parsing single email address

let address = try MimeEmailParser().parseSingleAddress(address: "jdeo@example.domain")

Some of the supported formats (for more examples check MimeEmailParserTests.swift source code)

let address = try MimeEmailParser().parseSingleAddress(address: "jdoe@example.domain")
let address = try MimeEmailParser().parseSingleAddress(address: "John Doe <jdoe@machine.example>")
let address = try MimeEmailParser().parseSingleAddress(address: "john.q.public@example.com")
let address = try MimeEmailParser().parseSingleAddress(address: "john.q.public@example.com")
let address = try MimeEmailParser().parseSingleAddress(address: "John !@M@! Doe <jdoe@machine.example>") // yes. it's a valid address 

Supports also "Q"-encoded email addresses:

// expected result: Address(Name: "Jörg Doe", Address: "joerg@example.com")
let address = try MimeEmailParser().parseSingleAddress(address: "=?iso-8859-1?q?J=F6rg_Doe?= <joerg@example.com>")

// expected result: Address(Name: "Jörg Doe", Address: "joerg@example.com")
let address = try MimeEmailParser().parseSingleAddress(address: "=?utf-8?q?J=C3=B6rg?=  =?utf-8?q?Doe?= <joerg@example.com>")

By RFC 5322 only utf-8 and ISO-8859-1 and ASCII is supported but MimeEmailParser doesn't acknowledge those limitations.

Parsing mulitple email addresses

// expected result: [Address(Name: "Mary Smith", Address: "mary@x.test"),Address(Name: nil, Address: "jdoe@example.org"),Address(Name: "Who?", Address: "<one@y.test>")]

let addresses = try MimeEmailParser().parseAddressList(addresses: "Mary Smith <mary@x.test>, jdoe@example.org, Who? <one@y.test>")

// expected results: Address(Name: "André Pirard", Address: "PIRARD@vm1.ulg.ac.be")
let addresses = try MimeEmailParser().parseAddressList(addresses: "=?ISO-8859-1?Q?Andr=E9?= Pirard <PIRARD@vm1.ulg.ac.be>")

// expected result: [Address(Name: nil, Address: "addr1@example.com"), Address(Name: nil, Address: "addr2@example.com"), Address(Name: "John", Address: "addr3@example.com")] 
let addresses = try MimeEmailParser().parseAddressList(addresses: "Group1: <addr1@example.com>;, Group 2: addr2@example.com;, John <addr3@example.com>")

Email Validation

MimeEmailParser can also be used for email validation.

do {
    _ = try MimeEmailParser().parseSingleAddress(address: "John Doe@foo.bar")
} catch EmailError.noAngleAddr {
}

Possible email format errors:

Error	Description
noAddrSpec	No email specified
utf8Invalid	Invalid character in address
leadingDotInAtom	Detected leading dot
doubleDotInAtom	Detected double dots
trailingDotInAtom	Detected trailing dot
unclosedQuotedString	Unclosed quotes in the name
badCharacter	Bad character in address
missingAtInAddrSpace	Missing @ symbol
noDomainInAddrSpec	Domain not specified
invalidEmailAddress	Email could not be parse (unknown)
missingWordInPhrase	Missing word in phrase
expectedComma	Missing comma in multiple email addresses
noAngleAddr	Likely meant to be "Full Name <...>"
unclosedAngleAddr	Missing trailing >
commendNotStartedWithParantheses	Failed parsing quoted string in comment
misformattedParentheticalComment	CFWS validation

Decoding "Q"-Encoded words

// expcted result: This is a horsey: 🐎
let decoded = try rfc2047.decodeRFC2047Word(word: "=?UTF-8?B?VGhpcyBpcyBhIGhvcnNleTog8J+Qjg==?=")

Contributing

The first thing you'll need to do is fork MimeEmailParser to your own GitHub repository. For instructions on how to do that, see the section titled Fork the repository.

Once you've got some changes that you'd like to submit upstream to the official MimeEmailParser repository, send me a Pull Request and I will try to review your changes in a timely manner.

Known Issues

• failing to parse utf-8 characters in domains and local address parts

License

MimeEmailParser is released under the MIT license. See LICENSE for details.