How to retrieve all attributes of an LDAP entry with golang query? - go

Question

I'm using the gopkg.in/ldap.v2 api to query an LDAP server, but was wondering how to retrieve all the attributes of an entry once it shows up in the query result? Here is the full program I have:
/*In order to use this program, the user needs to get the package by running the following command:
go get gopkg.in/ldap.v2*/
package main
import (
"fmt"
"strings"
"gopkg.in/ldap.v2"
"os"
)
//Gives constants to be used for binding to and searching the LDAP server.
const (
ldapServer = "127.0.0.1:389"
ldapBind = "cn=admin,dc=test123,dc=com"
ldapPassword = "Password"
filterDN = "(objectclass=*)"
baseDN = "dc=test123,dc=com"
loginUsername = "admin"
loginPassword = "Password"
)
//Main function, which is executed.
func main() {
conn, err := connect()
//If there is an error connecting to server, prints this
if err != nil {
fmt.Printf("Failed to connect. %s", err)
return
}
//Close the connection at a later time.
defer conn.Close()
//Declares err to be list(conn), and checks if any errors. It prints the error(s) if there are any.
if err := list(conn); err != nil {
fmt.Printf("%v", err)
return
}
/*
//Declares err to be auth(conn), and checks if any errors. It prints the error(s) if there are any.
if err := auth(conn); err != nil {
fmt.Printf("%v", err)
return
}*/
}
//This function is used to connect to the LDAP server.
func connect() (*ldap.Conn, error) {
conn, err := ldap.Dial("tcp", ldapServer)
if err != nil {
return nil, fmt.Errorf("Failed to connect. %s", err)
}
if err := conn.Bind(ldapBind, ldapPassword); err != nil {
return nil, fmt.Errorf("Failed to bind. %s", err)
}
return conn, nil
}
//This function is used to search the LDAP server as well as output the attributes of the entries.
func list(conn *ldap.Conn) error {
//This gets the command line argument and saves it in the form "(argument=*)"
arg := ""
filter := ""
if len(os.Args) > 1{
arg = os.Args[1]
fmt.Println(arg)
filter = "(" + arg + "=*)"
} else{
fmt.Println("You need to input an argument for an attribute to search. I.E. : \"go run anonymous_query.go cn\"")
}
result, err := conn.Search(ldap.NewSearchRequest(
baseDN,
ldap.ScopeWholeSubtree,
ldap.NeverDerefAliases,
0,
0,
false,
fmt.Sprintf(filter),
//To add anymore strings to the search, you need to add it here.
[]string{"dn", "o", "cn", "ou", "uidNumber", "objectClass",
"uid", "uidNumber", "gidNumber", "homeDirectory", "loginShell", "gecos",
"shadowMax", "shadowWarning", "shadowLastChange", "dc", "description", "entryCSN"},
nil,
))
if err != nil {
return fmt.Errorf("Failed to search users. %s", err)
}
//Prints all the attributes per entry
for _, entry := range result.Entries {
entry.Print()
fmt.Println()
}
return nil
}
//This function authorizes the user and binds to the LDAP server.
func auth(conn *ldap.Conn) error {
result, err := conn.Search(ldap.NewSearchRequest(
baseDN,
ldap.ScopeWholeSubtree,
ldap.NeverDerefAliases,
0,
0,
false,
filter(loginUsername),
[]string{"dn"},
nil,
))
if err != nil {
return fmt.Errorf("Failed to find user. %s", err)
}
if len(result.Entries) < 1 {
return fmt.Errorf("User does not exist")
}
if len(result.Entries) > 1 {
return fmt.Errorf("")
}
if err := conn.Bind(result.Entries[0].DN, loginPassword); err != nil {
fmt.Printf("Failed to auth. %s", err)
} else {
fmt.Printf("Authenticated successfuly!")
}
return nil
}
func filter(needle string) string {
res := strings.Replace(
filterDN,
"{username}",
needle,
-1,
)
return res
}
The issue I have is in this line:
//To add anymore strings to the search, you need to add it here.
[]string{"dn", "o", "cn", "ou", "uidNumber", "objectClass",
"uid", "uidNumber", "gidNumber", "homeDirectory", "loginShell", "gecos",
"shadowMax", "shadowWarning", "shadowLastChange", "dc", "description", "entryCSN"}
I would want to retrieve all the attributes of an LDAP entry rather than having to manually type all the attributes that I want from the query result. Another reason is because I don't know what attributes an entry may have.
Any help would be greatly appreciated. Thanks!

Answer 1

In the LDAP search operation, if you don't specify attributes for the search it will return the entries with all their attributes, so this will do the job:
result, err := conn.Search(ldap.NewSearchRequest(
baseDN,
ldap.ScopeWholeSubtree,
ldap.NeverDerefAliases,
0,
0,
false,
fmt.Sprintf(filter),
[]string{},
nil,
))