Querying an LDAP directory



The cfldap tag lets you search an LDAP directory. The tag returns a ColdFusion query object with the results, which you can use as you would any query result. When you query an LDAP directory, you specify the directory entry where the search starts and the attributes whose values to return. You can specify the search scope and attribute content filtering rules and use other attributes to further control the search.

Scope

The search scope sets the limits of a search. The default scope is the level below the distinguished name specified in the start attribute. This scope does not include the entry identified by the start attribute. For example, if the start attribute is “ou=support, o=adobe” the level below support is searched. You can restrict a query to the level of the start entry, or extend it to the entire subtree below the start entry.

Search filter

The search filter syntax has the form attribute operator value. The default filter, objectclass=*, returns all entries in the scope.

The following table lists the filter operators:

Operator

Example

Matches

=*

(mail=*)

All entries that contain a mail attribute.

=

(o=adobe)

Entries in which the organization name is adobe.

~=

(sn~=Hansen)

Entries with a surname that approximates Hansen. The matching rules for approximate matches vary among directory vendors, but anything that “sounds like” the search string should be matched. In this example, the directory server might return entries with the surnames Hansen and Hanson.

>=

(st>=ma)

The name “ma” and names appearing after “ma” in an alphabetical state attribute list.

<=

(st<=ma)

The name “ma” and names appearing before “ma” in an alphabetical state attribute list.

*

(o=macro*)

Organization names that start with “macro”.

 

(o=*media)

Organization names that end with “media”.

 

(o=mac*ia)

Organization names that start with “mac” and end with “ia”. You can use more than one * operator in a string; for example, m*ro*dia.

 

(o=*med*)

Organization names that contain the string “med”, including the exact string match “med”.

&

(&(o=adobe)

(co=usa))

Entries in which the organization name is “adobe” and the country is “usa”.

|

(|(o=adobe)

(sn=adobe)

(cn=adobe))

Entries in which the organization name is “adobe” or the surname is “adobe”, or the common name is “adobe”.

!

(!(STREET=*))

Entries that do not contain a StreetAddress attribute.

The Boolean operators & and | can operate on more than two attributes and precede all of the attributes on which they operate. You surround a filter with parentheses and use parentheses to group conditions.

If the pattern that you are matching contains an asterisk, left parenthesis, right parenthesis, backslash, or NUL character, use the following three-character escape sequence in place of the character:

Character

Escape sequence

*

\2A

(

\28

)

\29

\

\5C

NUL

\00

For example, to match the common name St*r Industries, use the filter:

(cn=St\2Ar Industries).

LDAP v3 supports an extensible match filter that permits server-specific matching rules. For more information on using extensible match filters, see your LDAP server documentation.

Searching and sorting notes

  • To search for multiple values of a multivalued attribute type, use the & operator to combine expressions for each attribute value. For example, to search for an entry in which cn=Robert Jones and cn=Bobby Jones, specify the following filter:

    filter="(&(cn=Robert Jones)(cn=Bobby Jones))"

  • You can use object classes as search filter attributes; for example, you can use the following search filter:

    filter="(objectclass=inetorgperson)"

  • To specify how query results are sorted, use the sort field to identify the attribute(s) to sort. By default, ColdFusion returns sorted results in case-sensitive ascending order. To specify descending order, case-insensitive sorting, or both, use the sortControl attribute.

  • ColdFusion requests the LDAP server to do the sorting. Doing so can have the following effects:

    • The sort order can differ between ColdFusion MX and previous versions.

    • If you specify sorting and the LDAP server does not support sorting, ColdFusion generates an error. To sort results from servers that do not support sorting, use a query of queries on the results.

  • Using filter operators to construct sophisticated search criteria can degrade performance if the LDAP server is slow to process the synchronous search routines that cfldap supports. Use the cfldap tag timeout and maxRows attributes to control the apparent performance of pages that perform queries, by limiting the number of entries and by exiting the query if the server does not respond in a specified time.

Getting all the attributes of an entry

Typically, you do not use a query that gets all the attributes in an entry. Such a query would return attributes that only the directory server uses. However, you can get all the attributes by specifying attributes="*" in your query.

If you do this, ColdFusion returns the results in a structure in which each element contains a single attribute name-value pair. The tag does not return a query object. ColdFusion does this because LDAP directory entries, unlike the rows in a relational table, vary depending on their object class.

For example, the following code retrieves the contents of the Airius directory:

<cfldap name="GetList" 
    server=#myServer# 
    action="query" 
    attributes="*" 
    scope="subtree" 
    start="o=airius.com" 
    sort="sn,cn">

This tag returns entries for all the people in the organization and entries for all the groups. The group entries have a different object class, and therefore different attributes from the person entries. If ColdFusion returned both types of entries in one query object, some rows would have only the group-specific attribute values and the other rows would have only person-specific attribute values. Instead, ColdFusion returns a structure in which each attribute is an entry.

Example: querying an LDAP directory

The following example uses the cfldap tag to get information about the people in the Airius corporation’s Santa Clara office. Users can enter all or part of a person’s name and get a list of matching names with their departments, e-mail addresses, and telephone numbers.

This example uses the sample Airius corporate directory that is distributed with the Netscape Directory Server. If you do not have access to this directory, modify the code to work with your LDAP directory.

  1. Create a file that looks like the following:

    <!--- This example shows the use of CFLDAP ---> 
<html> 
<head> <title>cfldap Query Example</title> </head> 
 
<h3>cfldap Query Example</h3> 
 
<body> 
<p>This tool queries the Airius.com database to locate all people in the company's  
    Santa Clara office whose common names contain the text entered in the form.</p> 
 
<p>Enter a full name, first name, last name, or name fragment.</p> 
 
<form action="cfldap.cfm" method="POST"> 
    <input type="text" name="name"><br><br> 
    <input type="submit" value="Search"> 
</form> 
<!--- make the LDAP query ---> 
<!-- Note that some search text is required. 
    A search filter of cn=** would cause an error --> 
<cfif (isdefined("form.name") AND (form.name IS NOT ""))> 
    <cfldap 
        server="ldap.airius.com" 
        action="query" 
        name="results" 
        start="ou=People, o=Airius.com" 
        scope="onelevel" 
        filter="(&(cn=*#form.Name#*)(l=Santa Clara))" 
        attributes="cn,sn,ou,mail,telephonenumber" 
        sort="ou,sn" 
        maxrows=100 
        timeout=20000 
    > 
 
<!--- Display results ---> 
    <table border=0 cellspacing=2 cellpadding=2> 
     <tr> 
        <th colspan=4><cfoutput>#results.RecordCount# matches found</cfoutput> 
        </th> 
     </tr> 
     <tr> 
        <th>Name</th> 
        <th>Department</th> 
        <th>E-Mail</th> 
        <th>Phone</th> 
     </tr> 
    <cfoutput query="results"> 
     <tr> 
        <td>#cn#</td> 
        <td>#listFirst(ou)#</td> 
        <td><a href="mailto:#mail#">#mail#</a></td> 
        <td>#telephonenumber#</td> 
    </tr> 
    </cfoutput> 
    </table> 
</cfif> 
     
</body> 
</html>

  2. Change the server attribute from ldap.airius.com to the name of your installation of the Airius database.

  3. Save the page as cfldap.cfm and run it in your browser.

Reviewing the code

The following table describes the code:

Code

Description

 
<form action="cfldap.cfm" method="POST"> 
     <input type="text" name="name"><br><br> 
     <input type="submit" value="Search"> 
</form>

Uses a form to get the name or name fragment to search for.

 
<cfif (isdefined("form.name") AND (form.name IS NOT ""))>

Ensures that the user has submitted the form. This is necessary because the form page is also the action page. Ensures that the user entered search text.

 
<cfldap 
         server="ldap.airius.com" 
         action="query" 
         name="results" 
         start="ou=People, o=Airius.com" 
         scope="onelevel" 
         filter="(&(cn=*#form.Name#*)(l=Santa Clara))" 
         attributes="cn,sn,ou,mail,telephonenumber" 
         sort="ou,sn" 
         maxrows=100 
         timeout=20000 
     >

Connects anonymously to LDAP server ldap.airius.com, query the directory, and return the results to a query object named results.

Starts the query at the directory entry that has the distinguished name ou=People, o=Airius.com, and searches the directory level immediately below this entry.

Requests records for entries that contain the location (l) attribute value "Santa Clara" and the entered text in the common name attribute.

Gets the common name, surname, organizational unit, e-mail address, and telephone number for each entry.

Sorts the results first by organization name, then by surname. Sorts in the default sorting order.

Limit the request to 100 entries. If the server does not return the data in 20 seconds, generates an error indicating that LDAP timed out.

 
<table border=0 cellspacing=2 cellpadding=2> 
      <tr> 
         <th colspan=4><cfoutput>#results.RecordCount# matches found</cfoutput> 
         </th> 
      </tr> 
      <tr> 
         <th>Name</th> 
         <th>Department</th> 
         <th>E-Mail</th> 
         <th>Phone</th> 
      </tr> 
     <cfoutput query="results"> 
      <tr> 
         <td>#cn#</td> 
         <td>#listFirst(ou)#</td> 
         <td><a href="mailto:#mail#">#mail#</a></td> 
         <td>#telephonenumber#</td> 
     </tr> 
     </cfoutput> 
     </table> 
 </cfif>

Starts a table to display the output

 

 

 

 

 

 

Displays the number of records returned.

 

Displays the common name, department, e-mail address, and telephone number of each entry.

Displays only the first entry in the list of organizational unit values. (For more information, see the description that follows this table.)

This search shows the use of a logical AND statement in a filter. It returns one attribute, the surname, that is used only for sorting the results.

In this query, the ou attribute value consists of two values in a comma-delimited list. One is the department name. The other is People. This is because the Airius database uses the ou attribute type twice:

  • In the distinguished names, at the second level of the directory tree, where it differentiates between organizational units such as people, groups, and directory servers

  • As the department identifier in each person’s entry

Because the attribute values are returned in order from the person entry to the directory tree root, the ListFirst function extracts the person’s department name.