first commit. Way too late.

shared/mongo.go

@@ -0,0 +1,101 @@
+package shared
+
+import (
+	"errors"
+	"fmt"
+	"labix.org/v2/mgo"
+	"net/url"
+	"strings"
+)
+
+var mongoClients = make(map[string]*mgo.Session)
+
+func GetCanonicalMongoURL(u string) (string, error) {
+	urlinfo, err := parseMongoURL(u)
+	if err != nil {
+		return "", err
+	}
+	return strings.Join(urlinfo.addrs, "/"), nil
+
+}
+
+func GetMongoClient(url string) (*mgo.Session, error) {
+	murl, err := GetCanonicalMongoURL(url)
+	if err != nil {
+		return nil, err
+	}
+	client, ok := mongoClients[murl]
+	if !ok {
+		return getNewMongoClient(url)
+	}
+	if client.Ping() != nil {
+		return getNewMongoClient(url)
+	}
+	return client, nil
+}
+
+func getNewMongoClient(url string) (*mgo.Session, error) {
+	client, err := mgo.Dial(url)
+	if err != nil {
+		return nil, err
+	}
+	murl, err := GetCanonicalMongoURL(url)
+	if err != nil {
+		return nil, err
+	}
+	mongoClients[murl] = client
+	return client, nil
+}
+
+type urlInfo struct {
+	addrs   []string
+	user    string
+	pass    string
+	db      string
+	options map[string]string
+}
+
+func isOptSep(c rune) bool {
+	return c == ';' || c == '&'
+}
+
+func parseMongoURL(s string) (*urlInfo, error) {
+	if strings.HasPrefix(s, "mongodb://") {
+		s = s[10:]
+	}
+	info := &urlInfo{options: make(map[string]string)}
+	if c := strings.Index(s, "?"); c != -1 {
+		for _, pair := range strings.FieldsFunc(s[c+1:], isOptSep) {
+			l := strings.SplitN(pair, "=", 2)
+			if len(l) != 2 || l[0] == "" || l[1] == "" {
+				return nil, errors.New("connection option must be key=value: " + pair)
+			}
+			info.options[l[0]] = l[1]
+		}
+		s = s[:c]
+	}
+	if c := strings.Index(s, "@"); c != -1 {
+		pair := strings.SplitN(s[:c], ":", 2)
+		if len(pair) > 2 || pair[0] == "" {
+			return nil, errors.New("credentials must be provided as user:pass@host")
+		}
+		var err error
+		info.user, err = url.QueryUnescape(pair[0])
+		if err != nil {
+			return nil, fmt.Errorf("cannot unescape username in URL: %q", pair[0])
+		}
+		if len(pair) > 1 {
+			info.pass, err = url.QueryUnescape(pair[1])
+			if err != nil {
+				return nil, fmt.Errorf("cannot unescape password in URL")
+			}
+		}
+		s = s[c+1:]
+	}
+	if c := strings.Index(s, "/"); c != -1 {
+		info.db = s[c+1:]
+		s = s[:c]
+	}
+	info.addrs = strings.Split(s, ",")
+	return info, nil
+}