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  <header>
    <copyright>
      <year>2012</year><year>2022</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.

    </legalnotice>

    <title>eldap</title>
    <prepared>Peter H&ouml;gfeldt</prepared>
    <docno></docno>
    <date>2000-06-20</date>
    <rev>B</rev>
  </header>
  <module since="OTP R15B01">eldap</module>
  <modulesummary>LDAP Client</modulesummary>
  <description>
    <p>This module provides a client api to the Lightweight Directory Access Protocol (LDAP).
    </p>
    <p>References:</p>
    <list type="bulleted">
      <item> <p>RFC 4510 - RFC 4519</p> </item>
      <item> <p>RFC 2830</p> </item>
    </list>
    <p>The above publications can be found at <url href="http://www.ietf.org">IETF</url>.
    </p>
  </description>

  <section>
    <title>DATA TYPES</title>
    <p>Type definitions that are used more than once in this module:
    </p>
    <taglist>
      <tag><c>handle()</c></tag>
      <item><p>Connection handle</p></item>

      <tag><c>attribute() =</c></tag>
      <item><p><c>{Type = string(), Values=[string()]}</c></p></item>

      <tag><c>modify_op()</c></tag>
      <item><p>See 
        <seemfa marker="#mod_add/2">mod_add/2</seemfa>, 
        <seemfa marker="#mod_delete/2">mod_delete/2</seemfa>,
        <seemfa marker="#mod_replace/2">mod_replace/2</seemfa>
      </p></item>

      <tag><c>scope()</c></tag>
      <item><p>See 
        <seemfa marker="#baseObject/0">baseObject/0</seemfa>, 
        <seemfa marker="#singleLevel/0">singleLevel/0</seemfa>, 
        <seemfa marker="#wholeSubtree/0">wholeSubtree/0</seemfa>
      </p></item>

      <tag><c>dereference()</c></tag>
      <item><p>See 
        <seemfa marker="#neverDerefAliases/0">neverDerefAliases/0</seemfa>, 
        <seemfa marker="#derefInSearching/0">derefInSearching/0</seemfa>, 
        <seemfa marker="#derefFindingBaseObj/0">derefFindingBaseObj/0</seemfa>, 
        <seemfa marker="#derefAlways/0">derefAlways/0</seemfa>
      </p></item>

      <tag><c>filter()</c></tag>
      <item><p>See 
        <seemfa marker="#present/1">present/1</seemfa>, 
        <seemfa marker="#substrings/2">substrings/2</seemfa>, 
        <seemfa marker="#equalityMatch/2">equalityMatch/2</seemfa>, 
        <seemfa marker="#greaterOrEqual/2">greaterOrEqual/2</seemfa>, 
        <seemfa marker="#lessOrEqual/2">lessOrEqual/2</seemfa>, 
        <seemfa marker="#approxMatch/2">approxMatch/2</seemfa>, 
        <seemfa marker="#extensibleMatch/2">extensibleMatch/2</seemfa>, 
        <seemfa marker="#'and'/1">'and'/1</seemfa>, 
        <seemfa marker="#'or'/1">'or'/1</seemfa>, 
        <seemfa marker="#'not'/1">'not'/1</seemfa>
      </p></item>

      <tag><c>return_value() = </c></tag>
      <item><p><c>ok | {ok, {referral,referrals()}} | {error,Error}</c>
      </p></item>

      <tag><c>referrals() =</c></tag>
      <item><p><c>[Address = string()]</c> The contents of <c>Address</c> is server dependent.
      </p></item>

    </taglist>
  </section>


  <funcs>
    <func>
      <name since="OTP R15B01">open([Host]) -> {ok, Handle} | {error, Reason}</name>
      <fsummary>Open a connection to an LDAP server.</fsummary>
      <type>
	<v>Handle = handle()</v>
      </type>
      <desc>
        <p>Setup a connection to an LDAP server, the <c>HOST</c>'s are tried in order. </p>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">open([Host], [Option]) -> {ok, Handle} | {error, Reason}</name>
      <fsummary>Open a connection to an LDAP server.</fsummary>
      <type>
	<v>Handle = handle()</v>
	<v>Option = {port, integer()} | {log, function()} | {timeout, integer()} | {ssl, boolean()} | {sslopts, list()} | {tcpopts, list()}</v>
      </type>
      <desc>
        <p>Setup a connection to an LDAP server, the <c>HOST</c>'s are tried in order.</p>
	<p>The log function takes three arguments, <c>fun(Level, FormatString, [FormatArg]) end</c>.</p>
	<p>Timeout set the maximum time in milliseconds that each server request may take.</p>
	<p>All TCP socket options are accepted except 
	  <c>active</c>, <c>binary</c>, <c>deliver</c>, <c>list</c>, <c>mode</c> and <c>packet</c>
	</p>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">close(Handle) -> ok</name>
      <fsummary>Shutdown the connection.</fsummary>
      <type>
	<v>Handle = handle()</v>
      </type>
      <desc>
        <p>Shutdown the connection after sending an unbindRequest to the server. If the connection is tls the connection
	will be closed with <c>ssl:close/1</c>, otherwise with <c>gen_tcp:close/1</c>.</p>
      </desc>
    </func>
    <func>
      <name since="OTP R16B03">start_tls(Handle, Options) -> return_value()</name>
      <fsummary>Upgrade a connection to TLS.</fsummary>
      <desc>
        <p>Same as start_tls(Handle, Options, infinity)</p>
      </desc>
    </func>
    <func>
      <name since="OTP R16B03">start_tls(Handle, Options, Timeout) -> return_value()</name>
      <fsummary>Upgrade a connection to TLS.</fsummary>
      <type>
	<v>Handle = handle()</v>
	<v>Options = ssl:ssl_options()</v>
	<v>Timeout = infinity | positive_integer()</v>
      </type>
      <desc>
        <p>Upgrade the connection associated with <c>Handle</c> to a tls connection if possible.</p>
	<p>The upgrade is done in two phases: first the server is asked for permission to upgrade. Second, if the request is acknowledged, the upgrade to tls is performed.</p>
	<p>Error responses from phase one will not affect the current encryption state of the connection. Those responses are:</p>
	<taglist>
	  <tag><c>tls_already_started</c></tag>
	  <item>The connection is already encrypted.  The connection is not affected.</item>
	  <tag><c>{response,ResponseFromServer}</c></tag>
	  <item>The upgrade was refused by the LDAP server.  The <c>ResponseFromServer</c> is an atom delivered byt the LDAP server explained in section 2.3 of rfc 2830. The connection is not affected, so it is still un-encrypted.</item>
	</taglist>
	<p>Errors in the second phase will however end the connection:</p>
	<taglist>
	  <tag><c>Error</c></tag>
	  <item>Any error responded from ssl:connect/3</item>
	</taglist>
	<p>The <c>Timeout</c> parameter is for the actual tls upgrade (phase 2) while the timeout in
	<seemfa marker="#open/2">eldap:open/2</seemfa> is used for the initial negotiation about
	upgrade (phase 1).
	</p>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">simple_bind(Handle, Dn, Password) -> return_value()</name>
      <fsummary>Authenticate the connection.</fsummary>
      <type>
	<v>Handle = handle()</v>
        <v>Dn = string()</v>
        <v>Password = string()</v>
      </type>
      <desc>
        <p>Authenticate the connection using simple authentication.</p>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">add(Handle, Dn, [Attribute]) -> return_value()</name>
      <fsummary>Add an entry.</fsummary>
      <type>
	<v>Handle = handle()</v>
        <v>Dn = string()</v>
	<v>Attribute = attribute()</v>
      </type>
      <desc>
	<p> Add an entry. The entry must not exist.</p>
	<code>
  add(Handle,
      "cn=Bill Valentine, ou=people, o=Example Org, dc=example, dc=com",
       [{"objectclass", ["person"]},
        {"cn", ["Bill Valentine"]},
        {"sn", ["Valentine"]},
        {"telephoneNumber", ["545 555 00"]}]
     )
	</code>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">delete(Handle, Dn) -> return_value()</name>
      <fsummary>Delete an entry.</fsummary>
      <type>
        <v>Dn = string()</v>
      </type>
      <desc>
	<p> Delete an entry.</p>
	<code>
  delete(Handle, "cn=Bill Valentine, ou=people, o=Example Org, dc=example, dc=com")
	</code>
      </desc>
    </func>

    <func>
      <name since="OTP R15B01">mod_add(Type, [Value]) -> modify_op()</name>
      <fsummary>Create a modification operation.</fsummary>
      <type>
        <v>Type = string()</v>
        <v>Value = string()</v>
      </type>
      <desc> <p> Create an add modification operation.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">mod_delete(Type, [Value]) -> modify_op()</name>
      <fsummary>Create a modification operation.</fsummary>
      <type>
        <v>Type = string()</v>
        <v>Value = string()</v>
      </type>
      <desc> <p> Create a delete modification operation.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">mod_replace(Type, [Value]) -> modify_op()</name>
      <fsummary>Create a modification operation.</fsummary>
      <type>
        <v>Type = string()</v>
        <v>Value = string()</v>
      </type>
      <desc> <p> Create a replace modification operation.</p> </desc>
    </func>

    <func>
      <name since="OTP R15B01">modify(Handle, Dn, [ModifyOp]) -> return_value()</name>
      <fsummary>Modify an entry.</fsummary>
      <type>
        <v>Dn = string()</v>
        <v>ModifyOp = modify_op()</v>
      </type>
      <desc>
	<p> Modify an entry.</p>
	<code>
  modify(Handle, "cn=Bill Valentine, ou=people, o=Example Org, dc=example, dc=com",
         [eldap:mod_replace("telephoneNumber", ["555 555 00"]),
	  eldap:mod_add("description", ["LDAP Hacker"]) ])
	</code>
      </desc>
    </func>
    <func>
      <name since="OTP 18.0">modify_password(Handle, Dn, NewPasswd) -> return_value() | {ok, GenPasswd}</name>
      <fsummary>Modify the password of a user.</fsummary>
      <type>
        <v>Dn = string()</v>
        <v>NewPasswd = string()</v>
      </type>
      <desc>
	<p>Modify the password of a user. See <seemfa marker="#modify_password/4">modify_password/4</seemfa>.</p>
      </desc>
    </func>
    <func>
      <name since="OTP 18.0">modify_password(Handle, Dn, NewPasswd, OldPasswd) -> return_value() | {ok, GenPasswd}</name>
      <fsummary>Modify the password of a user.</fsummary>
      <type>
        <v>Dn = string()</v>
        <v>NewPasswd = string()</v>
        <v>OldPasswd = string()</v>
        <v>GenPasswd = string()</v>
      </type>
      <desc>
	<p>Modify the password of a user.</p>
        <list type="bulleted">
          <item>
            <p><c>Dn</c>. The user to modify. Should be "" if the
            modify request is for the user of the LDAP session.</p>
          </item>
          <item>
            <p><c>NewPasswd</c>. The new password to set. Should be ""
            if the server is to generate the password. In this case,
            the result will be <c>{ok, GenPasswd}</c>.</p>
          </item>
          <item>
            <p><c>OldPasswd</c>. Sometimes required by server policy
            for a user to change their password. If not required, use
            <seemfa marker="#modify_password/3">modify_password/3</seemfa>.</p>
          </item>
        </list>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">modify_dn(Handle, Dn, NewRDN, DeleteOldRDN, NewSupDN) -> return_value()</name>
      <fsummary>Modify the DN of an entry.</fsummary>
      <type>
        <v>Dn = string()</v>
        <v>NewRDN = string()</v>
        <v>DeleteOldRDN = boolean()</v>
        <v>NewSupDN = string()</v>
      </type>
      <desc>
	<p> Modify the DN of an entry. <c>DeleteOldRDN</c> indicates
	whether the current RDN should be removed from the attribute list after the operation.
	<c>NewSupDN</c> is the new parent that the RDN shall be moved to.  If the old parent should
	remain as parent, <c>NewSupDN</c> shall be "".</p>
	<code>
  modify_dn(Handle, "cn=Bill Valentine, ou=people, o=Example Org, dc=example, dc=com ",
            "cn=Bill Jr Valentine", true, "")
	</code>
      </desc>
    </func>
    <func>
      <name since="OTP R15B01">search(Handle, SearchOptions) -> {ok, #eldap_search_result{}} | {ok, {referral,referrals()}} | {error, Reason}</name>
      <fsummary>Search the Directory</fsummary>
      <type>
        <v>SearchOptions = #eldap_search{} | [SearchOption]</v>
        <v>SearchOption = {base, string()} | {filter, filter()} | {scope, scope()}
	| {attributes, [string()]} | {deref, dereference()} |
	| {types_only, boolean()} | {timeout, integer()}
	</v>
      </type>
      <desc>
	<p>Search the directory with the supplied the SearchOptions.
	The base and filter options must be supplied.
	Default values: scope is <c>wholeSubtree()</c>, deref is <c>derefAlways()</c>,
	types_only is <c>false</c> and timeout is <c>0</c> (meaning infinity).
	</p>
	<code>
  Filter = eldap:substrings("cn", [{any,"V"}]),
  search(Handle, [{base, "dc=example, dc=com"}, {filter, Filter}, {attributes, ["cn"]}]),
	</code>
	<p>The <c>timeout</c> option in the <c>SearchOptions</c> is for the ldap server, while
	the timeout in <seemfa marker="#open/2">eldap:open/2</seemfa> is used for each
	individual request in the search operation.
	</p>
      </desc>
    </func>

    <func>
      <name since="OTP R15B01">baseObject() -> scope()</name>
      <fsummary>Create search scope.</fsummary>
      <desc> <p> Search baseobject only.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">singleLevel() -> scope()</name>
      <fsummary>Create search scope.</fsummary>
      <desc> <p> Search the specified level only, i.e. do not recurse.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">wholeSubtree() -> scope()</name>
      <fsummary>Create search scope.</fsummary>
      <desc> <p> Search the entire subtree.</p> </desc>
    </func>

    <func>
      <name since="OTP R15B01">neverDerefAliases() -> dereference()</name>
      <fsummary>Create search option.</fsummary>
      <desc> <p>Never dereference aliases, treat aliases as entries.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">derefAlways() -> dereference()</name>
      <fsummary>Create search option.</fsummary>
      <desc> <p>Always dereference aliases.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">derefInSearching() -> dereference()</name>
      <fsummary>Create search option.</fsummary>
      <desc> <p>Dereference aliases only when searching.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">derefFindingBaseObj() -> dereference()</name>
      <fsummary>Create search option.</fsummary>
      <desc> <p>Dereference aliases only in finding the base.</p> </desc>
    </func>

    <func>
      <name since="OTP R15B01">present(Type) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
      </type>
      <desc> <p>Create a filter which filters on attribute type presence.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">substrings(Type, [SubString]) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
	<v>SubString = {StringPart, string()}</v>
	<v>StringPart = initial | any | final</v>
      </type>
      <desc> <p>Create a filter which filters on substrings.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">equalityMatch(Type, Value) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
	<v>Value = string()</v>
      </type>
      <desc> <p>Create a equality filter.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">greaterOrEqual(Type, Value) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
	<v>Value = string()</v>
      </type>
      <desc> <p>Create a greater or equal filter.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">lessOrEqual(Type, Value) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
	<v>Value = string()</v>
      </type>
      <desc> <p>Create a less or equal filter.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">approxMatch(Type, Value) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Type = string()</v>
	<v>Value = string()</v>
      </type>
      <desc> <p>Create a approximation match filter.</p> </desc>
    </func>
    <func>
      <name since="OTP 17.4">extensibleMatch(MatchValue, OptionalAttrs) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>MatchValue = string()</v>
	<v>OptionalAttrs = [Attr]</v>
	<v>Attr = {matchingRule,string()} | {type,string()} | {dnAttributes,boolean()}</v>
      </type>
      <desc> <p>Creates an extensible match filter. For example, </p>
      <code>
  eldap:extensibleMatch("Bar", [{type,"sn"}, {matchingRule,"caseExactMatch"}]))
      </code>
      <p>creates a filter which performs a <c>caseExactMatch</c> on the attribute <c>sn</c> and matches with the value <c>"Bar"</c>. The default value of <c>dnAttributes</c> is <c>false</c>.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">'and'([Filter]) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Filter = filter()</v>
      </type>
      <desc> <p>Creates a filter where all <c>Filter</c> must be true.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">'or'([Filter]) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Filter = filter()</v>
      </type>
      <desc> <p>Create a filter where at least one of the <c>Filter</c> must be true.</p> </desc>
    </func>
    <func>
      <name since="OTP R15B01">'not'(Filter) -> filter()</name>
      <fsummary>Create search filter option.</fsummary>
      <type>
	<v>Filter = filter()</v>
      </type>
      <desc> <p>Negate a filter.</p> </desc>
    </func>
    <func>
      <name since="OTP 25.0">paged_result_control(PageSize) -&gt;
      {control, "1.2.840.113556.1.4.319", true, binary()}</name>
      <fsummary>Create a paged result control tuple</fsummary>
      <type>
        <v>PageSize = positive_integer()</v>
      </type>
      <desc>
        <p>Paged results is an extension to the LDAP protocol
        specified by RFC2696</p>
        <p>This function creates a control with the specified page
        size for use in
        <c>search/3</c>, for example:</p>
   	<code>
Control = eldap:paged_result_control(50),
{ok, SearchResults} = search(Handle, [{base, "dc=example, dc=com"}], [Control]),
	</code>     
      </desc>
    </func>
    <func>
      <name since="OTP 25.0">paged_result_control(PageSize, Cookie)
      -&gt; {control, "1.2.840.113556.1.4.319", true,
      binary()}</name>
      <fsummary>Create a paged result control tuple with the given
      Cookie</fsummary>
      <type>
        <v>PageSize = positive_integer()</v>
        <v>Cookie = binary()</v>
      </type>
      <desc>
        <p>Paged results is an extension to the LDAP protocol
        specified by RFC2696</p>
        <p>This function creates a control with the specified page
        size and cookie for use in
        <c>search/3</c> to retrieve the next results page.</p>
        <p>For example:</p>
        <code>
PageSize = 50,
Control1 = eldap:paged_result_control(PageSize),
{ok, SearchResults1} = search(Handle, [{base, "dc=example, dc=com"}], [Control1]),
%% retrieve the returned cookie from the search results
{ok, Cookie1} = eldap:paged_result_cookie(SearchResults1),
Control2 = eldap:paged_result_control(PageSize, Cookie1),
{ok, SearchResults2} = eldap:search(Handle, [{base, "dc=example,dc=com"}], [Control2]),
%% etc
	</code>
      </desc>
    </func>
    <func>
      <name since="OTP 25.0">paged_result_cookie(SearchResult)
      -&gt; binary()</name>
      <fsummary>Extract a cookie from search results for use in the
      subsequent search.</fsummary>
      <type>
        <v>SearchResult = #eldap_search_result{}</v>
      </type>
      <desc>
        <p>Paged results is an extension to the LDAP protocol
        specified by RFC2696.</p>
        <p>This function extracts the cookie returned from the
        server as a result of a paged search result.</p>
        <p>If the returned cookie is the empty string
        <c>""</c>, then these search results represent the last in
        the series.</p>
      </desc>
    </func>

  </funcs>

</erlref>

