lang: core: net: Add a new func for URL parsing

This is a first attempt to add a new function for URL parsing, using
go's net/url package and the simple API. This is still a barebones
implementation, there's possibility to expose more information. It also
includes simple tests.

lang/core/net/url_parser.go

@@ -0,0 +1,93 @@
+// Mgmt
+// Copyright (C) James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+// Additional permission under GNU GPL version 3 section 7
+//
+// If you modify this program, or any covered work, by linking or combining it
+// with embedded mcl code and modules (and that the embedded mcl code and
+// modules which link with this program, contain a copy of their source code in
+// the authoritative form) containing parts covered by the terms of any other
+// license, the licensors of this program grant you additional permission to
+// convey the resulting work. Furthermore, the licensors of this program grant
+// the original author, James Shubin, additional permission to update this
+// additional permission if he deems it necessary to achieve the goals of this
+// additional permission.
+
+package corenet
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
+	"github.com/purpleidea/mgmt/lang/types"
+	"github.com/purpleidea/mgmt/util/errwrap"
+)
+
+const (
+	urlParserFieldScheme   = "scheme"
+	urlParserFieldHost     = "host"
+	urlParserFieldPath     = "path"
+	urlParserFieldRawQuery = "raw_query"
+)
+
+var urlParserReturnType = fmt.Sprintf(
+	"struct{%s str; %s str; %s str; %s str}",
+	urlParserFieldScheme,
+	urlParserFieldHost,
+	urlParserFieldPath,
+	urlParserFieldRawQuery,
+)
+
+func init() {
+	simple.ModuleRegister(ModuleName, "url_parser", &simple.Scaffold{
+		T: types.NewType(fmt.Sprintf("func(str) %s", urlParserReturnType)),
+		F: URLParser,
+	})
+}
+
+// URLParser takes a URL as a string, and extracts the different components of
+// the URL: scheme, host, path, and query. The function will error out if the
+// given URL doesn't contain a valid URL, as this is a requirement of the
+// underlying net/url library. Note that additional fields may be added to the
+// output in the future.
+func URLParser(ctx context.Context, input []types.Value) (types.Value, error) {
+	u, err := url.Parse(input[0].Str())
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "error parsing the URL")
+	}
+	if u.Scheme == "" {
+		return nil, errwrap.Wrapf(err, "empty schemes are invalid")
+	}
+
+	v := types.NewStruct(types.NewType(urlParserReturnType))
+	if err := v.Set(urlParserFieldScheme, &types.StrValue{V: u.Scheme}); err != nil {
+		return nil, errwrap.Wrapf(err, "invalid scheme value")
+	}
+	if err := v.Set(urlParserFieldHost, &types.StrValue{V: u.Host}); err != nil {
+		return nil, errwrap.Wrapf(err, "invalid host value")
+	}
+	if err := v.Set(urlParserFieldPath, &types.StrValue{V: u.Path}); err != nil {
+		return nil, errwrap.Wrapf(err, "invalid path value")
+	}
+	if err := v.Set(urlParserFieldRawQuery, &types.StrValue{V: u.RawQuery}); err != nil {
+		return nil, errwrap.Wrapf(err, "invalid query value")
+	}
+
+	return v, nil
+}

lang/interpret_test/TestAstFunc2/url_parser.txtar

@@ -0,0 +1,22 @@
+-- main.mcl --
+
+import "net"
+import "fmt"
+
+$url1 = "https://www.example.com/search?q=mgmt"
+$url2 = "ftp://example.com/apath"
+$url3 = "https://www3.weird.url/?qu=ery"
+
+$url_parse1 = net.url_parser($url1)
+$url_parse2 = net.url_parser($url2)
+$url_parse3 = net.url_parser($url3)
+
+test [fmt.printf("%s %s %s %s", $url_parse1->scheme, $url_parse1->host, $url_parse1->path, $url_parse1->raw_query),] {}
+test [fmt.printf("%s %s %s %s", $url_parse2->scheme, $url_parse2->host, $url_parse2->path, $url_parse2->raw_query),] {}
+test [fmt.printf("%s %s %s %s", $url_parse3->scheme, $url_parse3->host, $url_parse3->path, $url_parse3->raw_query),] {}
+
+-- OUTPUT --
+
+Vertex: test[https www.example.com /search q=mgmt]
+Vertex: test[ftp example.com /apath ]
+Vertex: test[https www3.weird.url / qu=ery]