# imap_open

(PHP 4, PHP 5, PHP 7, PHP 8)

imap_open — Open an IMAP stream to a mailbox

### 说明

imap_open(
string `$mailbox`,
string `$user`,
string `$password`,
int `$flags` = 0,
int `$retries` = 0,
array `$options` = []
): IMAP\Connection|false

Opens an IMAP stream to a `mailbox`.

This function can also be used to open streams to POP3 and NNTP servers, but some functions and features are only available on IMAP servers.

### 参数

`mailbox`

  A mailbox name consists of a server and a mailbox path on this server. The special name `INBOX` stands for the current users personal mailbox. Mailbox names that contain international characters besides those in the printable ASCII space have to be encoded with imap_utf7_encode().

  警告

  Passing untrusted data to this parameter is insecure, unless imap.enable_insecure_rsh is disabled.

  The server part, which is enclosed in '{' and '}', consists of the servers name or ip address, an optional port (prefixed by ':'), and an optional protocol specification (prefixed by '/').

  The server part is mandatory in all mailbox parameters.

  All names which start with `{` are remote names, and are in the form `"{" remote_system_name [":" port] [flags] "}" [mailbox_name]` where:

  - `remote_system_name` - Internet domain name or bracketed IP address of server.
  - `port` - optional TCP port number, default is the default port for that service
  - `flags` - optional flags, see following table.
  - `mailbox_name` - remote mailbox name, default is INBOX

  Optional flags for names
  Flag | Description
  --- | ---
  `/service=`service | mailbox access service, default is "imap"
  `/user=`user | remote user name for login on the server
  `/authuser=`user | remote authentication user; if specified this is the user name whose password is used (e.g. administrator)
  `/anonymous` | remote access as anonymous user
  `/debug` | record protocol telemetry in application's debug log
  `/secure` | do not transmit a plaintext password over the network
  `/imap`, `/imap2`, `/imap2bis`, `/imap4`, `/imap4rev1` | equivalent to `/service=imap`
  `/pop3` | equivalent to `/service=pop3`
  `/nntp` | equivalent to `/service=nntp`
  `/norsh` | do not use rsh or ssh to establish a preauthenticated IMAP session
  `/ssl` | use the `Secure Socket Layer` to encrypt the session
  `/validate-cert` | validate certificates from TLS/SSL server (this is the default behavior)
  `/novalidate-cert` | do not validate certificates from TLS/SSL server, needed if server uses self-signed certificates
  `/tls` | force use of `start-TLS` to encrypt the session, and reject connection to servers that do not support it
  `/notls` | do not do `start-TLS` to encrypt the session, even with servers that support it
  `/readonly` | request read-only mailbox open (IMAP only; ignored on NNTP, and an error with SMTP and POP3)

`user`

  The user name

`password`

  The password associated with the `user`

`flags`

  The `flags` are a bit mask with one or more of the following:

  - `OP_READONLY` - Open mailbox read-only
  - `OP_ANONYMOUS` - Don't use or update a .newsrc for news (NNTP only)
  - `OP_HALFOPEN` - For IMAP and NNTP names, open a connection but don't open a mailbox.
  - `CL_EXPUNGE` - Expunge mailbox automatically upon mailbox close (see also imap_delete() and imap_expunge())
  - `OP_DEBUG` - Debug protocol negotiations
  - `OP_SHORTCACHE` - Short (`elt`-only) caching
  - `OP_SILENT` - Don't pass up events (internal use)
  - `OP_PROTOTYPE` - Return driver prototype
  - `OP_SECURE` - Don't do non-secure authentication
`retries`

  Number of maximum connect attempts

`options`

  Connection parameters, the following (string) keys maybe used to set one or more connection parameters:

  - `DISABLE_AUTHENTICATOR` - Disable authentication properties

### 返回值

Returns an IMAP\Connection instance on success, 或者在失败时返回 `false`.

### 更新日志

版本 | 说明
--- | ---
8.1.0 | Returns an IMAP\Connection instance now; previously, a resource was returned.

### 示例

示例 #1 Different use of imap_open()

`<?php
// To connect to an IMAP server running on port 143 on the local machine,
// do the following:
$mbox = imap_open("{localhost:143}INBOX", "user_id", "password");
// To connect to a POP3 server on port 110 on the local server, use:
$mbox = imap_open ("{localhost:110/pop3}INBOX", "user_id", "password");
// To connect to an SSL IMAP or POP3 server, add /ssl after the protocol
// specification:
$mbox = imap_open ("{localhost:993/imap/ssl}INBOX", "user_id", "password");
// To connect to an SSL IMAP or POP3 server with a self-signed certificate,
// add /ssl/novalidate-cert after the protocol specification:
$mbox = imap_open ("{localhost:995/pop3/ssl/novalidate-cert}", "user_id", "password");
// To connect to an NNTP server on port 119 on the local server, use:
$nntp = imap_open ("{localhost:119/nntp}comp.test", "", "");
// To connect to a remote server replace "localhost" with the name or the
// IP address of the server you want to connect to.
?>`

示例 #2 imap_open() example

`<?php
$mbox = imap_open("{imap.example.org:143}", "username", "password");
echo "<h1>Mailboxes</h1>\n";
$folders = imap_listmailbox($mbox, "{imap.example.org:143}", "*");
if ($folders == false) {
echo "Call failed<br />\n";
} else {
foreach ($folders as $val) {
echo $val . "<br />\n";
}
}
echo "<h1>Headers in INBOX</h1>\n";
$headers = imap_headers($mbox);
if ($headers == false) {
echo "Call failed<br />\n";
} else {
foreach ($headers as $val) {
echo $val . "<br />\n";
}
}
imap_close($mbox);
?>`

### 参见

- imap_close() - Close an IMAP stream

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