Python check email address

email-validate 1.1.2

Email validator with regex, blacklisted domains and SMTP checking.

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Лицензия: LGPL

Метки email, validation, verification, mx, verify

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Классификаторы

• Development Status
  • 2 — Pre-Alpha
  • Developers
  • OS Independent
  • Python
  • Python :: 3
  • Python :: 3 :: Only
  • Python :: 3.6
  • Python :: 3.7
  • Python :: 3.8
  • Python :: 3.9
  • Software Development :: Libraries :: Application Frameworks
  • Software Development :: Libraries :: Python Modules

  Описание проекта

  email-validate

  email-validate is a package for Python that check if an email is valid, not blacklisted, properly formatted and really exists.

  This module is for Python 3.6 and above!

  INSTALLATION

  You can install the package with pip:

  pip3 install email-validate 

  USAGE

  In [1]: from email_validate import validate, validate_or_fail In [2]: validate( . email_address='hello@00.pe', . check_format=True, . check_blacklist=True, . check_dns=True, . dns_timeout=10, . check_smtp=False, . smtp_debug=False) Out[2]: False In [3]: validate( . email_address='joe.us.yk@gmail.com', . check_format=True, . check_blacklist=True, . check_dns=True, . dns_timeout=10, . check_smtp=False, . smtp_debug=False) Out[3]: True 

  Parameters

  email_address : the email address to check

  check_format : check whether the email address has a valid structure; defaults to True

  check_blacklist : check the email against the blacklist of domains downloaded from DadouData temporary email data(daily update. ); defaults to True

  check_dns : check the DNS mx-records, defaults to True

  dns_timeout : seconds until DNS timeout; defaults to 10 seconds

  check_smtp : check whether the email actually exists by initiating an SMTP conversation; defaults to True

  smtp_timeout : seconds until SMTP timeout; defaults to 10 seconds

  smtp_helo_host : the hostname to use in SMTP HELO/EHLO; if set to None (the default), the fully qualified domain name of the local host is used

  smtp_from_address : the email address used for the sender in the SMTP conversation; if set to None (the default), the email_address parameter is used as the sender as well

  smtp_debug : activate smtplib ‘s debug output which always goes to stderr; defaults to False

  Result

  The function validate() returns the following results:

  True All requested checks were successful for the given email address.

  False At least one of the requested checks failed for the given email address.

  None None of the requested checks failed, but at least one of them yielded an ambiguous result. Currently, the SMTP check is the only check which can actually yield an ambigous result.

  Getting more information

  The function validate_or_fail() works exactly like validate() , except that it raises an exception in the case of validation failure and ambiguous result instead of returning False or None , respectively.

  All these exceptions descend from EmailValidationError . Please see below for the exact exceptions raised by the various checks. Note that all exception classes are defined in the module validate_email.exceptions .

  Please note that SMTPTemporaryError indicates an ambigous check result rather than a check failure, so if you use validate_or_fail() , you probably want to catch this exception.

  The checks

  By default, all checks are enabled, but each of them can be disabled by one of the check_. parameters. Note that, however, check_smtp implies check_dns .

  check_format

  Check whether the given email address conforms to the general format requirements of valid email addresses.

  validate_or_fail() raises AddressFormatError on any failure of this test.

  check_blacklist

  Check whether the domain part of the given email address (the part behind the «@») is known as a disposable and temporary email address domain. These are often used to register dummy users in order to spam or abuse some services.

  A list of such domains is maintained at DadouData temporary email data(daily update. ), and this module uses that list.

  validate_or_fail() raises DomainBlacklistedError if the email address belongs to a blacklisted domain.

  check_dns

  Check whether there is a valid list of servers responsible for delivering emails to the given email address.

  First, a DNS query is issued for the email address’ domain to retrieve a list of all MX records. That list is then stripped of duplicates and malformatted entries. If at the end of this procedure, at least one valid MX record remains, the check is considered successful.

  On failure of this check, validate_or_fail() raises one of the following exceptions, all of which descend from DNSError :

  DomainNotFoundError The domain of the email address cannot be found at all.

  NoNameserverError There is no nameserver for the domain.

  DNSTimeoutError A timeout occured when querying the nameserver. Note that the timeout period can be changed with the dns_timeout parameter.

  DNSConfigurationError The nameserver is misconfigured.

  NoMXError The nameserver does not list any MX records for the domain.

  NoValidMXError The nameserver lists MX records for the domain, but none of them is valid.

  check_smtp

  Check whether the given email address exists by simulating an actual email delivery.

  A connection to the SMTP server identified through the domain’s MX record is established, and an SMTP conversation is initiated up to the point where the server confirms the existence of the email address. After that, instead of actually sending an email, the conversation is cancelled.

  The module will try to negotiate a TLS connection with STARTTLS, and silently fall back to an unencrypted SMTP connection if the server doesn’t support it.

  If the SMTP server replies to the RCPT TO command with a code 250 (success) response, the check is considered successful.

  If the SMTP server replies with a code 5xx (permanent error) response at any point in the conversation, the check is considered failed.

  If the SMTP server cannot be connected, unexpectedly closes the connection, or replies with a code 4xx (temporary error) at any stage of the conversation, the check is considered ambiguous.

  If there is more than one valid MX record for the domain, they are tried in order of priority until the first time the check is either successful or failed. Only in case of an ambiguous check result, the next server is tried, and only if the check result is ambiguous for all servers, the overall check is considered ambigous as well.

  On failure of this check or on ambiguous result, validate_or_fail() raises one of the following exceptions, all of which descend from SMTPError :

  AddressNotDeliverableError The SMTP server permanently refused the email address. Technically, this means that the server replied to the RCPT TO command with a code 5xx response.

  SMTPCommunicationError The SMTP server refused to even let us get to the point where we could ask it about the email address. Technically, this means that the server sent a code 5xx response either immediately after connection, or as a reply to the EHLO (or HELO ) or MAIL FROM commands.

  SMTPTemporaryError A temporary error occured during the check for all available MX servers. This is considered an ambigous check result. For example, greylisting is a frequent cause for this.

  All of the above three exceptions provide further detail about the error response(s) in the exception’s instance variable error_messages .

  Update data source

  The package contains an auto-updater for downloading and updating the built-in blacklist.txt. It will run on each module load (and installation), but will try to update the content only if the file is older than 5 days, and if the content is not the same that’s already downloaded.

  The update can be triggered manually:

  from validate_email.updater import update_builtin_blacklist update_builtin_blacklist(force: bool = False, background: bool = True, callback: Callable = None) -> Optional[Thread] 

  force : forces the update even if the downloaded/installed file is fresh enough.

  background : starts the update in a Thread so it won’t make your code hang while it’s updating. If you set this to true, the function will return the Thread used for starting the update so you can join() it if necessary.

  callback : An optional Callable (function/method) to be called when the update is done.

  TODO

  Источник

  Python: Validate Email Address with Regular Expressions (RegEx)

  

  Regular Expressions, or RegEx for short, are expressions of patterns that can be used for text search and replace actions, validations, string splitting, and much more. These patterns consist of characters, digits and special characters, in such a form that the pattern matches certain segments of text we’re searching through.

  Regular Expressions are widely used for pattern-matching, and various programming languages have interfaces for representing them, as well as interacting with the matches results.

  In this article, we will take a look at how to validate email addresses in Python, using Regular Expressions.

  If you would like to learn more about Python’s interface with Regular Expressions, read our Guide to Regular Expressions in Python!

  General-Purpose Email Regular Expression

  It’s worth noting that there is no such regular expression that matches every possible valid email address. Although, there are expressions that can match most valid email addresses.

  We need to define what kind of email address format are we looking for. The most common email format is:

  (username)@(domainname).(top-leveldomain) 

  Thus, we can boil it down to a pattern of the @ symbol dividing the prefix from the domain segment.

  The prefix is the recipient;s name — a string that may contain uppercase and lowercase letters, numbers, and some special characters like the . (dot), — (hyphen), and _ (underscore).

  The domain consists of its name and a top-level domain divided by a . (dot) symbol. The domain name can have uppercase and lowercase letters, numbers, and — (hyphen) symbols. Additionally, the top-level domain name must be at least 2 characters long (either all uppercase or lowercase letters), but can be longer.

  Note: There are a lot more detailed rules regarding valid emails, such as character count, more specific characters that can be used, etc. We’ll be taking a look at an extended, highly fail-proof Regular Expression as defined by RFC5322 after the general-purpose approach.

  In simple terms, our email Regular Expression could look like this:

  (string1)@(string2).(2+characters) 

  This would match correctly for email addresses such as:

  [email protected] [email protected] [email protected] 

  Again, using the same expression, these email addresses would fail:

  [email protected] [email protected] [email protected] 

  It’s worth noting that the strings shouldn’t contain certain special characters, lest they break the form again. Additionally, the top-level domain can’t be .. . Accounting for those cases as well, we can put these rules down into a concrete expression that takes in a few more cases into account than the first representation:

  A special character in the prefix cannot be just before the @ symbol, nor can the prefix start with it, so we made sure that there is at least one alphanumeric character before and after every special character.

  As for the domain, an email can contain a few top-level domains divided with a dot.

  Obviously, this regex is more complicated than the first one, but it covers all of the rules we have defined for the email format. Yet again, it can probably fail to properly validate some edge case that we haven’t thought of.

  Validate Email Address with Python

  The re module contains classes and methods to represent and work with Regular Expressions in Python, so we’ll import it into our script. The method that we will be using is re.fullmatch(pattern, string, flags) . This method returns a match object only if the whole string matches the pattern, in any other case it returns None .

  Note: re.fullmatch() was introduced in Python 3.4, before that, re.match() was used instead. On newer versions, fullmatch() is preferred.

  Источник

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