added docstrings, added some static type hints and also lint. (#141)

* added docstrings, added some static type hints and also lint.

* added doc strings and changed some internal variable names for more clarity.

* make flake8 happy

* add descriptive docstrings and type hints in waybackpy/cdx_snapshot.py

* remove useless code and add docstrings and also lint using pylint.

* remove unwarented test

* added docstrings, lint using pylint and add a raise on 509 SC

* added docstrings and lint with pylint

* lint

* add doc strings and lint

* add docstrings and lint

tests/test_cdx_utils.py

@@ -53,10 +53,6 @@ def test_get_response() -> None:
     response = get_response(url, headers=headers)
     assert not isinstance(response, Exception) and response.status_code == 200
 
-    url = "http/wwhfhfvhvjhmom"
-    with pytest.raises(WaybackError):
-        get_response(url, headers=headers)
-
 
 def test_check_filters() -> None:
     filters: List[str] = []

waybackpy/availability_api.py

@@ -1,9 +1,32 @@
+"""
+This module interfaces the Wayback Machine's availability API.
+
+The interface could be useful for looking up archives and finding archives
+that are close to a specific date and time.
+
+It has a class called WaybackMachineAvailabilityAPI, and the class has
+methods such as:
+
+near() for looking up archives close to a specific date and time.
+
+oldest() for retrieving the first archive URL of the webpage.
+
+newest() for retrieving the latest archive of an URL.
+
+The Wayback Machine Availability response should be a valid JSON and
+if it is not then an exception, InvalidJSONInAvailabilityAPIResponse is raised.
+
+If the Availability API returned valid JSON but archive URL could not be found
+it it then ArchiveNotInAvailabilityAPIResponse is raised.
+"""
+
 import json
 import time
 from datetime import datetime
 from typing import Any, Dict, Optional
 
 import requests
+from requests.models import Response
 
 from .exceptions import (
     ArchiveNotInAvailabilityAPIResponse,
@@ -22,38 +45,43 @@ class WaybackMachineAvailabilityAPI(object):
     def __init__(
         self, url: str, user_agent: str = DEFAULT_USER_AGENT, max_tries: int = 3
     ) -> None:
+
         self.url = str(url).strip().replace(" ", "%20")
         self.user_agent = user_agent
         self.headers: Dict[str, str] = {"User-Agent": self.user_agent}
-        self.payload = {"url": self.url}
+        self.payload: Dict[str, str] = {"url": self.url}
-        self.endpoint = "https://archive.org/wayback/available"
+        self.endpoint: str = "https://archive.org/wayback/available"
-        self.max_tries = max_tries
+        self.max_tries: int = max_tries
-        self.tries = 0
+        self.tries: int = 0
-        self.last_api_call_unix_time = int(time.time())
+        self.last_api_call_unix_time: int = int(time.time())
-        self.api_call_time_gap = 5
+        self.api_call_time_gap: int = 5
         self.JSON: Optional[ResponseJSON] = None
 
     @staticmethod
     def unix_timestamp_to_wayback_timestamp(unix_timestamp: int) -> str:
         """
-        Converts Unix time to wayback Machine timestamp.
+        Converts Unix time to wayback Machine timestamp and the Wayback Machine
+        timestamp format is yyyyMMddhhmmss.
         """
+
         return datetime.utcfromtimestamp(int(unix_timestamp)).strftime("%Y%m%d%H%M%S")
 
     def __repr__(self) -> str:
         """
         Same as string representation, just return the archive URL as a string.
         """
+
         return str(self)
 
     def __str__(self) -> str:
         """
-        String representation of the class. If atleast one API call was successfully
+        String representation of the class. If atleast one API
-        made then return the archive URL as a string. Else returns None.
+        call was successfully made then return the archive URL
+        as a string. Else returns "".
         """
 
-        # String must not return anything other than a string object
+        # String should not return anything other than a string object
-        # So, if some asks for string repr before making the API requests
+        # So, if a string repr is asked for before making any API requests
         # just return ""
         if not self.JSON:
             return ""
@@ -62,26 +90,36 @@ class WaybackMachineAvailabilityAPI(object):
 
     def json(self) -> Optional[ResponseJSON]:
         """
-        Makes the API call to the availability API can set the JSON response
+        Makes the API call to the availability API and set the JSON response
-        to the JSON attribute of the instance and also returns the JSON attribute.
+        to the JSON attribute of the instance and also returns the JSON
+        attribute.
+
+        time_diff and sleep_time makes sure that you are not making too many
+        requests in a short interval of item, making too many requests is bad
+        as Wayback Machine may reject them above a certain threshold.
+
+        The end-user can change the api_call_time_gap attribute of the instance
+        to increase or decrease the default time gap between two successive API
+        calls, but it is not recommended to increase it.
         """
+
         time_diff = int(time.time()) - self.last_api_call_unix_time
         sleep_time = self.api_call_time_gap - time_diff
 
         if sleep_time > 0:
             time.sleep(sleep_time)
 
-        self.response = requests.get(
+        self.response: Response = requests.get(
             self.endpoint, params=self.payload, headers=self.headers
         )
         self.last_api_call_unix_time = int(time.time())
         self.tries += 1
         try:
             self.JSON = self.response.json()
-        except json.decoder.JSONDecodeError:
+        except json.decoder.JSONDecodeError as json_decode_error:
             raise InvalidJSONInAvailabilityAPIResponse(
                 f"Response data:\n{self.response.text}"
-            )
+            ) from json_decode_error
 
         return self.JSON
 
@@ -91,15 +129,17 @@ class WaybackMachineAvailabilityAPI(object):
         If JSON attribute of the instance is None it implies that the either
         the the last API call failed or one was never made.
 
-        If not JSON or if JSON but no timestamp in the JSON response then returns
+        If not JSON or if JSON but no timestamp in the JSON response then
-        the maximum value for datetime object that is possible.
+        returns the maximum value for datetime object that is possible.
 
-        If you get an URL as a response form the availability API it is guaranteed
+        If you get an URL as a response form the availability API it is
-        that you can get the datetime object from the timestamp.
+        guaranteed that you can get the datetime object from the timestamp.
         """
+
         if self.JSON is None or "archived_snapshots" not in self.JSON:
             return datetime.max
-        elif (
+
+        if (
             self.JSON is not None
             and "archived_snapshots" in self.JSON
             and self.JSON["archived_snapshots"] is not None
@@ -110,21 +150,23 @@ class WaybackMachineAvailabilityAPI(object):
             return datetime.strptime(
                 self.JSON["archived_snapshots"]["closest"]["timestamp"], "%Y%m%d%H%M%S"
             )
-        else:
+
         raise ValueError("Could not get timestamp from result")
 
     @property
     def archive_url(self) -> str:
         """
-        Reads the the JSON response data and tries to get the timestamp and returns
+        Reads the the JSON response data and returns
-        the timestamp if found else returns None.
+        the timestamp if found and if not found raises
+        ArchiveNotInAvailabilityAPIResponse.
         """
+
         archive_url = ""
         data = self.JSON
 
-        # If the user didn't used oldest, newest or near but tries to access the
+        # If the user didn't invoke oldest, newest or near but tries to access the
-        # archive_url attribute then, we assume they are fine with any archive
+        # archive_url attribute then assume they are fine with any archive
-        # and invoke the oldest archive function.
+        # and invoke the oldest method.
         if not data:
             self.oldest()
 
@@ -137,7 +179,7 @@ class WaybackMachineAvailabilityAPI(object):
                 self.json()  # It makes a new API call
                 data = self.JSON  # json() updated the value of JSON attribute
 
-            # Even if after we exhausted teh max_tries, then we give up and
+            # If we exhausted the max_tries, then we give up and
             # raise exception.
 
             if not data or not data["archived_snapshots"]:
@@ -160,6 +202,7 @@ class WaybackMachineAvailabilityAPI(object):
         Prepends zero before the year, month, day, hour and minute so that they
         are conformable with the YYYYMMDDhhmmss wayback machine timestamp format.
         """
+
         return "".join(
             str(kwargs[key]).zfill(2)
             for key in ["year", "month", "day", "hour", "minute"]
@@ -167,18 +210,21 @@ class WaybackMachineAvailabilityAPI(object):
 
     def oldest(self) -> "WaybackMachineAvailabilityAPI":
         """
-        Passing the year 1994 should return the oldest archive because
+        Passes the date 1994-01-01 to near which should return the oldest archive
-        wayback machine was started in May, 1996 and there should be no archive
+        because Wayback Machine was started in May, 1996 and it is assumed that
-        before the year 1994.
+        there would be no archive older than January 1, 1994.
         """
-        return self.near(year=1994)
+
+        return self.near(year=1994, month=1, day=1)
 
     def newest(self) -> "WaybackMachineAvailabilityAPI":
         """
-        Passing the current UNIX time should be sufficient to get the newest
+        Passes the current UNIX time to near() for retrieving the newest archive
-        archive considering the API request-response time delay and also the
+        from the availability API.
-        database lags on Wayback machine.
+
+        We assume that wayback machine can not archive the future of a webpage.
         """
+
         return self.near(unix_timestamp=int(time.time()))
 
     def near(
@@ -191,16 +237,18 @@ class WaybackMachineAvailabilityAPI(object):
         unix_timestamp: Optional[int] = None,
     ) -> "WaybackMachineAvailabilityAPI":
         """
-        The main method for this Class, oldest and newest methods are dependent on this
+        The main method for the Class, oldest() and newest() are dependent on it.
-        method.
 
         It generates the timestamp based on the input either by calling the
         unix_timestamp_to_wayback_timestamp or wayback_timestamp method with
         appropriate arguments for their respective parameters.
+
         Adds the timestamp to the payload dictionary.
+
         And finally invoking the json method to make the API call then returns
         the instance.
         """
+
         if unix_timestamp:
             timestamp = self.unix_timestamp_to_wayback_timestamp(unix_timestamp)
         else:

waybackpy/cdx_api.py

@@ -1,3 +1,14 @@
+"""
+This module interfaces the Wayback Machine's CDX server API.
+
+The module has WaybackMachineCDXServerAPI which should be used by the users of
+this module to consume the CDX server API.
+
+WaybackMachineCDXServerAPI has a snapshot method that yields the snapshots, and
+the snapshots are yielded as instances of the CDXSnapshot class.
+"""
+
+
 from typing import Dict, Generator, List, Optional, cast
 
 from .cdx_snapshot import CDXSnapshot
@@ -16,6 +27,11 @@ from .utils import DEFAULT_USER_AGENT
 class WaybackMachineCDXServerAPI(object):
     """
     Class that interfaces the CDX server API of the Wayback Machine.
+
+    snapshot() returns a generator that can be iterated upon by the end-user,
+    the generator returns the snapshots/entries as instance of CDXSnapshot to
+    make the usage easy, just use '.' to get any attribute as the attributes are
+    accessible via a dot ".".
     """
 
     # start_timestamp: from, can not use from as it's a keyword
@@ -53,9 +69,35 @@ class WaybackMachineCDXServerAPI(object):
     def cdx_api_manager(
         self, payload: Dict[str, str], headers: Dict[str, str], use_page: bool = False
     ) -> Generator[str, None, None]:
+        """
+        Manages the API calls for the instance, it automatically selects the best
+        parameters by looking as the query of the end-user. For bigger queries
+        automatically use the CDX pagination API and for smaller queries use the
+        normal API.
+
+        CDX Server API is a complex API and to make it easy for the end user to
+        consume it the CDX manager(this method) handles the selection of the
+        API output, whether to use the pagination API or not.
+
+        For doing large/bulk queries, the use of the Pagination API is
+        recommended by the Wayback Machine authors. And it determines if the
+        query would be large or not by using the showNumPages=true parameter,
+        this tells the number of pages of CDX DATA that the pagination API
+        will return.
+
+        If the number of page is less than 2 we use the normal non-pagination
+        API as the pagination API is known to lag and for big queries it should
+        not matter but for queries where the number of pages are less this
+        method chooses accuracy over the pagination API.
+        """
+
+        # number of pages that will returned by the pagination API.
+        # get_total_pages adds the showNumPages=true param to pagination API
+        # requests.
+        # This is a special query that will return a single number indicating
+        # the number of pages.
         total_pages = get_total_pages(self.url, self.user_agent)
-        # If we only have two or less pages of archives then we care for more accuracy
+
-        # pagination API is lagged sometimes
         if use_page is True and total_pages >= 2:
             blank_pages = 0
             for i in range(total_pages):
@@ -78,11 +120,11 @@ class WaybackMachineCDXServerAPI(object):
         else:
             payload["showResumeKey"] = "true"
             payload["limit"] = str(self.limit)
-            resumeKey = None
+            resume_key = None
             more = True
             while more:
-                if resumeKey:
+                if resume_key:
-                    payload["resumeKey"] = resumeKey
+                    payload["resumeKey"] = resume_key
 
                 url = full_url(self.endpoint, params=payload)
                 res = get_response(url, headers=headers)
@@ -102,13 +144,16 @@ class WaybackMachineCDXServerAPI(object):
 
                     if len(second_last_line) == 0:
 
-                        resumeKey = lines[-1].strip()
+                        resume_key = lines[-1].strip()
-                        text = text.replace(resumeKey, "", 1).strip()
+                        text = text.replace(resume_key, "", 1).strip()
                         more = True
 
                 yield text
 
     def add_payload(self, payload: Dict[str, str]) -> None:
+        """
+        Adds the payload to the payload dictionary.
+        """
         if self.start_timestamp:
             payload["from"] = self.start_timestamp
 
@@ -122,17 +167,35 @@ class WaybackMachineCDXServerAPI(object):
             payload["matchType"] = self.match_type
 
         if self.filters and len(self.filters) > 0:
-            for i, f in enumerate(self.filters):
+            for i, _filter in enumerate(self.filters):
-                payload["filter" + str(i)] = f
+                payload["filter" + str(i)] = _filter
 
         if self.collapses and len(self.collapses) > 0:
-            for i, f in enumerate(self.collapses):
+            for i, collapse in enumerate(self.collapses):
-                payload["collapse" + str(i)] = f
+                payload["collapse" + str(i)] = collapse
 
         # Don't need to return anything as it's dictionary.
         payload["url"] = self.url
 
     def snapshots(self) -> Generator[CDXSnapshot, None, None]:
+        """
+        This function yields the CDX data lines as snapshots.
+
+        As it is a generator it exhaustible, the reason that this is
+        a generator and not a list are:
+
+        a) CDX server API can return millions of entries for a query and list
+        is not suitable for such cases.
+
+        b) Preventing memory usage issues, as told before this method may yield
+        millions of records for some queries and your system may not have enough
+        memory for such a big list. Also Remember this if outputing to Jupyter
+        Notebooks.
+
+        The objects yielded by this method are instance of CDXSnapshot class,
+        you can access the attributes of the entries as the attribute of the instance
+        itself.
+        """
         payload: Dict[str, str] = {}
         headers = {"User-Agent": self.user_agent}
 
@@ -144,18 +207,25 @@ class WaybackMachineCDXServerAPI(object):
         if self.collapses != []:
             self.use_page = False
 
-        texts = self.cdx_api_manager(payload, headers, use_page=self.use_page)
+        entries = self.cdx_api_manager(payload, headers, use_page=self.use_page)
 
-        for text in texts:
+        for entry in entries:
 
-            if text.isspace() or len(text) <= 1 or not text:
+            if entry.isspace() or len(entry) <= 1 or not entry:
                 continue
 
-            snapshot_list = text.split("\n")
+            # each line is a snapshot aka entry of the CDX server API.
+            # We are able to split the page by lines because it only
+            # splits the lines on a sinlge page and not all the entries
+            # at once, thus there should be no issues of too much memory usage.
+            snapshot_list = entry.split("\n")
 
             for snapshot in snapshot_list:
 
-                if len(snapshot) < 46:  # 14 + 32 (timestamp+digest)
+                # 14 + 32 == 46 ( timestamp + digest ), ignore the invalid entries.
+                # they are invalid if their length is smaller than sum of length
+                # of a standard wayback_timestamp and standard digest of an entry.
+                if len(snapshot) < 46:
                     continue
 
                 properties: Dict[str, Optional[str]] = {
@@ -168,16 +238,16 @@ class WaybackMachineCDXServerAPI(object):
                     "length": None,
                 }
 
-                prop_values = snapshot.split(" ")
+                property_value = snapshot.split(" ")
 
-                prop_values_len = len(prop_values)
+                total_property_values = len(property_value)
-                properties_len = len(properties)
+                warranted_total_property_values = len(properties)
 
-                if prop_values_len != properties_len:
+                if total_property_values != warranted_total_property_values:
                     raise WaybackError(
-                        f"Snapshot returned by Cdx API has {prop_values_len} "
+                        f"Snapshot returned by CDX API has {total_property_values} prop"
-                        f"properties instead of expected {properties_len} properties.\n"
+                        f"erties instead of expected {warranted_total_property_values} "
-                        f"Problematic Snapshot: {snapshot}"
+                        f"properties.\nProblematic Snapshot: {snapshot}"
                     )
 
                 (
@@ -188,6 +258,6 @@ class WaybackMachineCDXServerAPI(object):
                     properties["statuscode"],
                     properties["digest"],
                     properties["length"],
-                ) = prop_values
+                ) = property_value
 
                 yield CDXSnapshot(cast(Dict[str, str], properties))

waybackpy/cdx_snapshot.py

@@ -1,30 +1,83 @@
+"""
+Module that contains the CDXSnapshot class, CDX records are casted
+to CDXSnapshot objects for easier access.
+
+The CDX index format is plain text data. Each line ('record') indicates a
+crawled document. And these lines are casted to CDXSnapshot.
+"""
+
+
 from datetime import datetime
 from typing import Dict
 
 
 class CDXSnapshot(object):
     """
-    Class for the CDX snapshot lines returned by the CDX API,
+    Class for the CDX snapshot lines('record') returned by the CDX API,
     Each valid line of the CDX API is casted to an CDXSnapshot object
-    by the CDX API interface.
+    by the CDX API interface, just use "." to access any attribute of the
+    CDX server API snapshot.
+
     This provides the end-user the ease of using the data as attributes
     of the CDXSnapshot.
+
+    The string representation of the class is identical to the line returned
+    by the CDX server API.
+
+    Besides all the attributes of the CDX server API this class also provides
+    archive_url attribute, yes it is the archive url of the snapshot.
+
+    Attributes of the this class and what they represents and are useful for:
+
+    urlkey: The document captured, expressed as a SURT
+            SURT stands for Sort-friendly URI Reordering Transform, and is a
+            transformation applied to URIs which makes their left-to-right
+            representation better match the natural hierarchy of domain names.
+            A URI <scheme://domain.tld/path?query> has SURT
+            form <scheme://(tld,domain,)/path?query>.
+
+    timestamp: The timestamp of the archive, format is yyyyMMddhhmmss and type
+               is string.
+
+    datetime_timestamp: The timestamp as a datetime object.
+
+    original: The original URL of the archive. If archive_url is
+    https://web.archive.org/web/20220113130051/https://google.com then the
+    original URL is https://google.com
+
+    mimetype: The document’s file type. e.g. text/html
+
+    statuscode: HTTP response code for the document at the time of its crawling
+
+    digest: Base32-encoded SHA-1 checksum of the document for discriminating
+            with others
+
+    length: Document’s volume of bytes in the WARC file
+
+    archive_url: The archive url of the snapshot, this is not returned by the
+                 CDX server API but created by this class on init.
     """
 
     def __init__(self, properties: Dict[str, str]) -> None:
-        self.urlkey = properties["urlkey"]
+        self.urlkey: str = properties["urlkey"]
-        self.timestamp = properties["timestamp"]
+        self.timestamp: str = properties["timestamp"]
-        self.datetime_timestamp = datetime.strptime(self.timestamp, "%Y%m%d%H%M%S")
+        self.datetime_timestamp: datetime = datetime.strptime(
-        self.original = properties["original"]
+            self.timestamp, "%Y%m%d%H%M%S"
-        self.mimetype = properties["mimetype"]
+        )
-        self.statuscode = properties["statuscode"]
+        self.original: str = properties["original"]
-        self.digest = properties["digest"]
+        self.mimetype: str = properties["mimetype"]
-        self.length = properties["length"]
+        self.statuscode: str = properties["statuscode"]
-        self.archive_url = (
+        self.digest: str = properties["digest"]
+        self.length: str = properties["length"]
+        self.archive_url: str = (
             f"https://web.archive.org/web/{self.timestamp}/{self.original}"
         )
 
     def __str__(self) -> str:
+        """
+        The string representation is same as the line returned by the
+        CDX server API for the snapshot.
+        """
         return (
             f"{self.urlkey} {self.timestamp} {self.original} "
             f"{self.mimetype} {self.statuscode} {self.digest} {self.length}"

waybackpy/cdx_utils.py

@@ -1,3 +1,10 @@
+"""
+Utility functions required for accessing the CDX server API.
+
+These are here in this module so that we don’t make any module too
+big.
+"""
+
 import re
 from typing import Any, Dict, List, Optional, Union
 from urllib.parse import quote
@@ -11,28 +18,44 @@ from .utils import DEFAULT_USER_AGENT
 
 
 def get_total_pages(url: str, user_agent: str = DEFAULT_USER_AGENT) -> int:
+    """
+    When using the pagination use adding showNumPages=true to the request
+    URL makes the CDX server return an integer which is the number of pages
+    of CDX pages available for us to query using the pagination API.
+    """
+
     endpoint = "https://web.archive.org/cdx/search/cdx?"
     payload = {"showNumPages": "true", "url": str(url)}
     headers = {"User-Agent": user_agent}
     request_url = full_url(endpoint, params=payload)
     response = get_response(request_url, headers=headers)
+
     if isinstance(response, requests.Response):
         return int(response.text.strip())
-    else:
     raise response
 
 
 def full_url(endpoint: str, params: Dict[str, Any]) -> str:
+    """
+    As the function's name already implies that it returns
+    full URL, but why we need a function for generating full URL?
+    The CDX server can support multiple arguments for parameters
+    such as filter and collapse and this function adds them without
+    overwriting earlier added arguments.
+    """
+
     if not params:
         return endpoint
-    full_url = endpoint if endpoint.endswith("?") else (endpoint + "?")
+    _full_url = endpoint if endpoint.endswith("?") else (endpoint + "?")
+
     for key, val in params.items():
         key = "filter" if key.startswith("filter") else key
         key = "collapse" if key.startswith("collapse") else key
-        amp = "" if full_url.endswith("?") else "&"
+        amp = "" if _full_url.endswith("?") else "&"
         val = quote(str(val), safe="")
-        full_url += f"{amp}{key}={val}"
+        _full_url += f"{amp}{key}={val}"
-    return full_url
+
+    return _full_url
 
 
 def get_response(
@@ -40,29 +63,31 @@ def get_response(
     headers: Optional[Dict[str, str]] = None,
     retries: int = 5,
     backoff_factor: float = 0.5,
-    # no_raise_on_redirects=False,
 ) -> Union[requests.Response, Exception]:
+    """
+    Make get request to the CDX server and return the response.
+    """
+
     session = requests.Session()
+
     retries_ = Retry(
         total=retries,
         backoff_factor=backoff_factor,
         status_forcelist=[500, 502, 503, 504],
     )
-    session.mount("https://", HTTPAdapter(max_retries=retries_))
 
-    try:
+    session.mount("https://", HTTPAdapter(max_retries=retries_))
     response = session.get(url, headers=headers)
     session.close()
     return response
-    except Exception as e:
-        reason = str(e)
-        exc_message = f"Error while retrieving {url}.\n{reason}"
-        exc = WaybackError(exc_message)
-        exc.__cause__ = e
-        raise exc
 
 
 def check_filters(filters: List[str]) -> None:
+    """
+    Check that the filter arguments passed by the end-user are valid.
+    If not valid then raise WaybackError.
+    """
+
     if not isinstance(filters, list):
         raise WaybackError("filters must be a list.")
 
@@ -81,9 +106,15 @@ def check_filters(filters: List[str]) -> None:
 
 
 def check_collapses(collapses: List[str]) -> bool:
+    """
+    Check that the collapse arguments passed by the end-user are valid.
+    If not valid then raise WaybackError.
+    """
+
     if not isinstance(collapses, list):
         raise WaybackError("collapses must be a list.")
-    elif len(collapses) == 0:
+
+    if len(collapses) == 0:
         return True
 
     for collapse in collapses:
@@ -103,18 +134,26 @@ def check_collapses(collapses: List[str]) -> bool:
 
 
 def check_match_type(match_type: Optional[str], url: str) -> bool:
+    """
+    Check that the match_type argument passed by the end-user is valid.
+    If not valid then raise WaybackError.
+    """
+
     legal_match_type = ["exact", "prefix", "host", "domain"]
+
     if not match_type:
         return True
-    elif "*" in url:
+
+    if "*" in url:
         raise WaybackError(
             "Can not use wildcard in the URL along with the match_type arguments."
         )
-    elif match_type not in legal_match_type:
+
+    if match_type not in legal_match_type:
         exc_message = (
             f"{match_type} is not an allowed match type.\n"
             "Use one from 'exact', 'prefix', 'host' or 'domain'"
         )
         raise WaybackError(exc_message)
-    else:
+
     return True

waybackpy/cli.py

@@ -1,3 +1,7 @@
+"""
+Module that makes waybackpy a CLI tool.
+"""
+
 import json as JSON
 import os
 import random
@@ -19,7 +23,10 @@ from .wrapper import Url
 def echo_availability_api(
     availability_api_instance: WaybackMachineAvailabilityAPI, json: bool
 ) -> None:
-    click.echo("Archive URL:")
+    """
+    Output availability API depending functions.
+    Near, oldest and newest output by this method.
+    """
     if not availability_api_instance.archive_url:
         archive_url = (
             "NO ARCHIVE FOUND - The requested URL is probably "
@@ -29,6 +36,7 @@ def echo_availability_api(
         )
     else:
         archive_url = availability_api_instance.archive_url
+    click.echo("Archive URL:")
     click.echo(archive_url)
     if json:
         click.echo("JSON response:")
@@ -36,6 +44,10 @@ def echo_availability_api(
 
 
 def save_urls_on_file(url_gen: Generator[str, None, None]) -> None:
+    """
+    Save output of CDX API on file.
+    Mainly here because of backwards compatibility.
+    """
     domain = None
     sys_random = random.SystemRandom()
     uid = "".join(
@@ -51,8 +63,8 @@ def save_urls_on_file(url_gen: Generator[str, None, None]) -> None:
             domain = "domain-unknown" if match is None else match.group(1)
             file_name = f"{domain}-urls-{uid}.txt"
             file_path = os.path.join(os.getcwd(), file_name)
-            with open(file_path, "a") as f:
+            with open(file_path, "a") as file:
-                f.write(f"{url}\n")
+                file.write(f"{url}\n")
 
         click.echo(url)
 
@@ -269,6 +281,7 @@ def main(  # pylint: disable=no-value-for-parameter
     """
     if version:
         click.echo(f"waybackpy version {__version__}")
+
     elif show_license:
         click.echo(
             requests.get(
@@ -277,6 +290,7 @@ def main(  # pylint: disable=no-value-for-parameter
         )
     elif url is None:
         click.echo("No URL detected. Please provide an URL.", err=True)
+
     elif (
         not version
         and not oldest
@@ -291,14 +305,17 @@ def main(  # pylint: disable=no-value-for-parameter
             "Use --help flag for help using waybackpy.",
             err=True,
         )
+
     elif oldest:
         availability_api = WaybackMachineAvailabilityAPI(url, user_agent=user_agent)
         availability_api.oldest()
         echo_availability_api(availability_api, json)
+
     elif newest:
         availability_api = WaybackMachineAvailabilityAPI(url, user_agent=user_agent)
         availability_api.newest()
         echo_availability_api(availability_api, json)
+
     elif near:
         availability_api = WaybackMachineAvailabilityAPI(url, user_agent=user_agent)
         near_args = {}
@@ -309,6 +326,7 @@ def main(  # pylint: disable=no-value-for-parameter
                 near_args[key] = arg
         availability_api.near(**near_args)
         echo_availability_api(availability_api, json)
+
     elif save:
         save_api = WaybackMachineSaveAPI(url, user_agent=user_agent)
         save_api.save()
@@ -319,15 +337,17 @@ def main(  # pylint: disable=no-value-for-parameter
         if headers:
             click.echo("Save API headers:")
             click.echo(save_api.headers)
+
     elif known_urls:
         wayback = Url(url, user_agent)
         url_gen = wayback.known_urls(subdomain=subdomain)
 
         if file:
             return save_urls_on_file(url_gen)
-        else:
+
         for url in url_gen:
             click.echo(url)
+
     elif cdx:
         filters = list(cdx_filter)
         collapses = list(collapse)

waybackpy/save_api.py

@@ -1,3 +1,10 @@
+"""
+This module interfaces the Wayback Machine's SavePageNow (SPN) API.
+
+The module has WaybackMachineSaveAPI class which should be used by the users of
+this module to use the SavePageNow API.
+"""
+
 import re
 import time
 from datetime import datetime
@@ -8,7 +15,7 @@ from requests.adapters import HTTPAdapter
 from requests.structures import CaseInsensitiveDict
 from urllib3.util.retry import Retry
 
-from .exceptions import MaximumSaveRetriesExceeded, TooManyRequestsError
+from .exceptions import MaximumSaveRetriesExceeded, TooManyRequestsError, WaybackError
 from .utils import DEFAULT_USER_AGENT
 
 
@@ -47,7 +54,7 @@ class WaybackMachineSaveAPI(object):
 
         if self._archive_url:
             return self._archive_url
-        else:
+
         return self.save()
 
     def get_save_request_headers(self) -> None:
@@ -66,6 +73,7 @@ class WaybackMachineSaveAPI(object):
         to be very unreliable thus if it fails first check opening
         the response URL yourself in the browser.
         """
+
         session = requests.Session()
         retries = Retry(
             total=self.total_save_retries,
@@ -79,11 +87,24 @@ class WaybackMachineSaveAPI(object):
         self.status_code = self.response.status_code
         self.response_url = self.response.url
         session.close()
+
         if self.status_code == 429:
+            # why wait 5 minutes and 429?
+            # see https://github.com/akamhy/waybackpy/issues/97
             raise TooManyRequestsError(
-                "Seem to be refused to request by the server. "
+                f"Can not save '{self.url}'. "
-                "Save Page Now receives up to 15 URLs per minutes. "
+                f"Save request refused by the server. "
-                "Wait a moment and run again."
+                f"Save Page Now limits saving 15 URLs per minutes. "
+                f"Try waiting for 5 minutes and then try again."
+            )
+
+        # why 509?
+        # see https://github.com/akamhy/waybackpy/pull/99
+        # also https://t.co/xww4YJ0Iwc
+        if self.status_code == 509:
+            raise WaybackError(
+                f"Can not save '{self.url}'. You have probably reached the "
+                f"limit of active sessions."
             )
 
     def archive_url_parser(self) -> Optional[str]:
@@ -146,13 +167,17 @@ class WaybackMachineSaveAPI(object):
         the Wayback Machine to serve cached archive if last archive was captured
         before last 45 minutes.
         """
-        regex = r"https?://web\.archive.org/web/([0-9]{14})/http"
-        m = re.search(regex, str(self._archive_url))
-        if m is None or len(m.groups()) != 1:
-            raise ValueError("Could not get timestamp")
-        string_timestamp = m.group(1)
-        timestamp = datetime.strptime(string_timestamp, "%Y%m%d%H%M%S")
 
+        regex = r"https?://web\.archive.org/web/([0-9]{14})/http"
+        match = re.search(regex, str(self._archive_url))
+
+        if match is None or len(match.groups()) != 1:
+            raise ValueError(
+                f"Can not parse timestamp from archive URL, '{self._archive_url}'."
+            )
+
+        string_timestamp = match.group(1)
+        timestamp = datetime.strptime(string_timestamp, "%Y%m%d%H%M%S")
         timestamp_unixtime = time.mktime(timestamp.timetuple())
         instance_birth_time_unixtime = time.mktime(self.instance_birth_time.timetuple())
 

waybackpy/utils.py

@@ -1,3 +1,7 @@
+"""
+Utility functions and shared variables like DEFAULT_USER_AGENT are here.
+"""
+
 import requests
 
 from . import __version__
@@ -8,6 +12,7 @@ DEFAULT_USER_AGENT: str = (
 
 
 def latest_version_pypi(package_name: str, user_agent: str = DEFAULT_USER_AGENT) -> str:
+    """Latest waybackpy version on PyPi."""
     request_url = "https://pypi.org/pypi/" + package_name + "/json"
     headers = {"User-Agent": user_agent}
     response = requests.get(request_url, headers=headers)
@@ -20,13 +25,14 @@ def latest_version_pypi(package_name: str, user_agent: str = DEFAULT_USER_AGENT)
         and data["info"]["version"] is not None
     ):
         return str(data["info"]["version"])
-    else:
+
     raise ValueError("Could not get latest pypi version")
 
 
 def latest_version_github(
     package_name: str, user_agent: str = DEFAULT_USER_AGENT
 ) -> str:
+    """Latest waybackpy version on GitHub."""
     request_url = (
         "https://api.github.com/repos/akamhy/" + package_name + "/releases?per_page=1"
     )
@@ -40,5 +46,5 @@ def latest_version_github(
         and "tag_name" in data[0]
     ):
         return str(data[0]["tag_name"])
-    else:
+
     raise ValueError("Could not get latest github version")

waybackpy/wrapper.py

@@ -1,3 +1,9 @@
+"""
+This module exists because backwards compatibility matters.
+Don't touch this or add any new functionality here and don't use
+the Url class.
+"""
+
 from datetime import datetime, timedelta
 from typing import Generator, Optional
 
@@ -49,12 +55,14 @@ class Url(object):
 
         if not isinstance(self.timestamp, datetime):
             raise TypeError("timestamp must be a datetime")
-        elif self.timestamp == datetime.max:
+
+        if self.timestamp == datetime.max:
             return td_max.days
-        else:
+
         return (datetime.utcnow() - self.timestamp).days
 
     def save(self) -> "Url":
+        """Save the URL on wayback machine."""
         self.wayback_machine_save_api = WaybackMachineSaveAPI(
             self.url, user_agent=self.user_agent
         )
@@ -72,7 +80,7 @@ class Url(object):
         minute: Optional[int] = None,
         unix_timestamp: Optional[int] = None,
     ) -> "Url":
-
+        """Returns the archive of the URL close to a date and time."""
         self.wayback_machine_availability_api.near(
             year=year,
             month=month,
@@ -85,16 +93,19 @@ class Url(object):
         return self
 
     def oldest(self) -> "Url":
+        """Returns the oldest archive of the URL."""
         self.wayback_machine_availability_api.oldest()
         self.set_availability_api_attrs()
         return self
 
     def newest(self) -> "Url":
+        """Returns the newest archive of the URL."""
         self.wayback_machine_availability_api.newest()
         self.set_availability_api_attrs()
         return self
 
     def set_availability_api_attrs(self) -> None:
+        """Set the attributes for total backwards compatibility."""
         self.archive_url = self.wayback_machine_availability_api.archive_url
         self.JSON = self.wayback_machine_availability_api.JSON
         self.timestamp = self.wayback_machine_availability_api.timestamp()
@@ -102,6 +113,10 @@ class Url(object):
     def total_archives(
         self, start_timestamp: Optional[str] = None, end_timestamp: Optional[str] = None
     ) -> int:
+        """
+        Returns an integer which indicates total number of archives for an URL.
+        Useless in my opinion, only here because of backwards compatibility.
+        """
         cdx = WaybackMachineCDXServerAPI(
             self.url,
             user_agent=self.user_agent,
@@ -122,6 +137,7 @@ class Url(object):
         end_timestamp: Optional[str] = None,
         match_type: str = "prefix",
     ) -> Generator[str, None, None]:
+        """Yields known URLs for any URL."""
         if subdomain:
             match_type = "domain"
         if host:
@@ -137,4 +153,4 @@ class Url(object):
         )
 
         for snapshot in cdx.snapshots():
-            yield (snapshot.original)
+            yield snapshot.original