How to resolve the algorithm URL parser step by step in the Wren programming language

Published on 12 May 2024 09:40 PM
#Wren

How to resolve the algorithm URL parser step by step in the Wren programming language

Table of Contents

Problem Statement

URLs are strings with a simple syntax:

Parse a well-formed URL to retrieve the relevant information:   scheme, domain, path, ...

Note:   this task has nothing to do with URL encoding or URL decoding.

According to the standards, the characters: only need to be percent-encoded   (%)   in case of possible confusion. Also note that the path, query and fragment are case sensitive, even if the scheme and domain are not. The way the returned information is provided (set of variables, array, structured, record, object,...) is language-dependent and left to the programmer, but the code should be clear enough to reuse. Extra credit is given for clear error diagnostics.

According to T. Berners-Lee foo://example.com:8042/over/there?name=ferret#nose     should parse into:

urn:example:animal:ferret:nose     should parse into:

other URLs that must be parsed include:

Let's start with the solution:

Step by Step solution about How to resolve the algorithm URL parser step by step in the Wren programming language

Source code in the wren programming language

var urlParse = Fn.new { |url|
    var parseUrl = "URL      = " + url
    var index
    if ((index = url.indexOf("//")) && index >= 0 && url[0...index].count { |c| c == ":" } == 1) {
        // parse the scheme
        var scheme = url.split("//")
        parseUrl = parseUrl + "\n" + "Scheme   = " + scheme[0][0..-2]
        // parse the domain
        var domain = scheme[1].split("/")
        // check if the domain includes a username, password and port
        if (domain[0].contains("@")) {
            var cred = domain[0].split("@")
            var split = [cred[0], ""]
            if (cred[0].contains(".")) {
                split = cred[0].split(".")
            } else if (cred[0].contains(":")) {
                split = cred[0].split(":")
            }
            var username = split[0]
            var password = split[1]
            parseUrl = parseUrl + "\n" + "Username = " + username
            if (password != "") parseUrl = parseUrl + "\n" + "Password = " + password
            // check if the domain has a port
            if (cred[1].contains(":")) {
                split = cred[1].split(":")
                var host = split[0]
                var port = ":" + split[1]
                parseUrl = parseUrl + "\n" + "Domain   = " + host + "\n" + "Port     = " + port
            } else {
                parseUrl = parseUrl + "\n" + "Domain   = " + cred[1]
            }
        } else if (domain[0].contains(":") && !domain[0].contains("[") && !domain[0].contains("]")) {
            var split = domain[0].split(":")
            var host = split[0]
            var port = ":" + split[1]
            parseUrl = parseUrl + "\n" + "Domain   = " + host + "\n" + "Port     = " + port
        } else if (domain[0].contains("[") && domain[0].contains("]:")) {
            var split = domain[0].split("]")
            var host = split[0] + "]"
            var port = ":" + split[1][1..-1]
            parseUrl = parseUrl + "\n" + "Domain   = " + host + "\n" + "Port     = " + port
        } else {
            parseUrl = parseUrl + "\n" + "Domain   = " + domain[0]
        }
        // parse the path if it exists
        if (domain.count > 1) {
            var path = "/"
            for (i in 1...domain.count) {
                if (i < domain.count - 1) {
                    path = path + domain[i] + "/"
                } else if (domain[i].contains("?")) {
                    var split = domain[i].split("?")
                    path = path + split[0]
                    if (domain[i].contains("#")) {
                        var split2 = split[1].split("#")
                        var query = split2[0]
                        var fragment = split2[1]
                        path = path + "\n" + "Query    = " + query + "\n" + "Fragment = " + fragment
                    } else {
                        var query = split[1]
                        path = path + "\n" + "Query    = " + query
                    }
                } else if (domain[i].contains("#")) {
                    var split = domain[i].split("#")
                    var fragment = split[1]
                    path = path + split[0] + "\n" + "Fragment = " + fragment
                } else {
                    path = path + domain[i]
                }
            }
            parseUrl = parseUrl + "\n" + "Path     = " + path
        }
    } else if (url.contains(":")) {
        var index = url.indexOf(":")
        var scheme = url[0...index]
        parseUrl = parseUrl + "\n" + "Scheme   = " + scheme + "\n"
        var path = url[index+1..-1]
        if (!path.contains("?")) {
            parseUrl = parseUrl + "Path     = " + path
        } else {
            var split = path.split("?")
            var query = split[1]
            parseUrl = parseUrl + "Path     = " + split[0] + "\n"
            if (!query.contains("#")) {
                parseUrl = parseUrl + "Query    = " + query
            } else {
                split = query.split("#")
                var fragment = split[1]
                parseUrl = parseUrl + "Query    = " + split[0] + "Fragment = " + fragment
            }
        }
    } else {
        parseUrl = parseUrl + "\n" + "Invalid!!!"
    }
    System.print(parseUrl)
    System.print()
}

var urls = [
    "foo://example.com:8042/over/there?name=ferret#nose",
    "urn:example:animal:ferret:nose",
    "jdbc:mysql://test_user:ouupppssss@localhost:3306/sakila?profileSQL=true",
    "ftp://ftp.is.co.za/rfc/rfc1808.txt",
    "http://www.ietf.org/rfc/rfc2396.txt#header1",
    "ldap://[2001:db8::7]/c=GB?objectClass=one&objectClass=two",
    "mailto:John.Doe@example.com",
    "news:comp.infosystems.www.servers.unix",
    "tel:+1-816-555-1212",
    "telnet://192.0.2.16:80/",
    "urn:oasis:names:specification:docbook:dtd:xml:4.1.2",
    "ssh://alice@example.com",
    "https://bob:pass@example.com/place",
    "http://example.com/?a=1&b=2+2&c=3&c=4&d=\%65\%6e\%63\%6F\%64\%65\%64"
]
for (url in urls) urlParse.call(url)

You may also check:How to resolve the algorithm Modular inverse step by step in the Bracmat programming language
You may also check:How to resolve the algorithm Character codes step by step in the Picat programming language
You may also check:How to resolve the algorithm Multiplication tables step by step in the HolyC programming language
You may also check:How to resolve the algorithm Averages/Arithmetic mean step by step in the Quackery programming language
You may also check:How to resolve the algorithm Hello world/Graphical step by step in the Jsish programming language