Add support for distributor TME (Issue #76)

docs/usage.rst

@@ -26,7 +26,7 @@ circuit boards developed with KiCad. Typical use is as follows:
 4. Open the ``schem.xlsx`` spreadsheet using Microsoft Excel, LibreOffice Calc, or Google Sheets.
    Then enter the number of boards that you need to build and see
    the prices for the total board and individual parts when purchased from 
-   several different distributors (KiCost currently supports Digi-Key, Mouser, Newark, Farnell and RS).
+   several different distributors (KiCost currently supports Digi-Key, Mouser, Newark, Farnell, RS and TME).
    All of the pricing information reflects the quantity discounts currently in effect at
    each distributor.
    The spreadsheet also shows the current inventory of each part from each distributor so you can tell

kicost/distributors/tme/__init__.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+__author__ ='Adam Heinrich'
+__email__ = 'adam@adamh.cz'
+
+from .tme import *
+
+# Place information about this distributor into the distributor dictionary.
+from .. import distributors
+distributors.update(
+    {
+        'tme': {
+            'module': 'tme', # The directory name containing this file.
+            'scrape': 'web',     # Allowable values: 'web' or 'local'.
+            'label': 'TME',  # Distributor label used in spreadsheet columns.
+            'order_cols': ['part_num', 'purch', 'refs'],  # Sort-order for online orders.
+            'order_delimiter': ' ',  # Delimiter for online orders.
+            # Formatting for distributor header in worksheet.
+            'wrk_hdr_format': {
+                'font_size': 14,
+                'font_color': 'white',
+                'bold': True,
+                'align': 'center',
+                'valign': 'vcenter',
+                'bg_color': '#0C4DA1'  # TME blue
+            }
+        }
+    }
+)

kicost/distributors/tme/tme.py

@@ -0,0 +1,229 @@
+# MIT license
+#
+# Copyright (C) 2015 by XESS Corporation
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+# Inserted by Pasteurize tool.
+from __future__ import print_function
+from __future__ import unicode_literals
+from __future__ import division
+from __future__ import absolute_import
+from builtins import zip
+from builtins import range
+from builtins import int
+from builtins import str
+from future import standard_library
+standard_library.install_aliases()
+
+import future
+
+import re
+import difflib
+import json
+from bs4 import BeautifulSoup
+import http.client # For web scraping exceptions.
+from .. import urlencode, urlquote, urlsplit, urlunsplit, urlopen, Request
+from .. import HTML_RESPONSE_RETRIES
+from .. import WEB_SCRAPE_EXCEPTIONS
+from .. import FakeBrowser
+from ...kicost import PartHtmlError
+from ...kicost import logger, DEBUG_OVERVIEW, DEBUG_DETAILED, DEBUG_OBSESSIVE
+
+def __ajax_details(pn):
+    '''Load part details from TME using XMLHttpRequest'''
+    data = urlencode({
+        'symbol': pn,
+        'currency': 'USD'
+    }).encode("utf-8")
+    req = FakeBrowser('http://www.tme.eu/en/_ajax/ProductInformationPage/_getStocks.html')
+    req.add_header('X-Requested-With', 'XMLHttpRequest')
+    for _ in range(HTML_RESPONSE_RETRIES):
+        try:
+            response = urlopen(req, data)
+            r = response.read()
+            break
+        except WEB_SCRAPE_EXCEPTIONS:
+            logger.log(DEBUG_DETAILED,'Exception while web-scraping {} from {}'.format(pn, dist))
+            pass
+    else: # Couldn't get a good read from the website.
+        logger.log(DEBUG_OBSESSIVE,'No AJAX data for {} from {}'.format(pn, dist))
+        return None, None
+
+    try:
+        p = json.loads(r)['Products'][0]
+        html_tree = BeautifulSoup(p['PriceTpl'].replace("\n", ""), "lxml")
+        quantity = p['InStock']
+        return html_tree, quantity
+    except (ValueError, KeyError, IndexError):
+        logger.log(DEBUG_OBSESSIVE, 'Could not obtain AJAX data from TME!')
+        return None, None
+
+def get_price_tiers(html_tree):
+    '''Get the pricing tiers from the parsed tree of the TME product page.'''
+    price_tiers = {}
+    try:
+        pn = get_part_num(html_tree)
+        if pn == '':
+            return price_tiers
+
+        ajax_tree, quantity = __ajax_details(pn)
+        if ajax_tree is None:
+            return price_tiers
+
+        qty_strs = []
+        price_strs = []
+        for tr in ajax_tree.find('tbody', id='prices_body').find_all('tr'):
+            td = tr.find_all('td')
+            if len(td) == 3:
+                qty_strs.append(td[0].text)
+                price_strs.append(td[2].text)
+
+        qtys_prices = list(zip(qty_strs, price_strs))
+        for qty_str, price_str in qtys_prices:
+            try:
+                qty = re.search('(\s*)([0-9,]+)', qty_str).group(2)
+                qty = int(re.sub('[^0-9]', '', qty))
+                price_tiers[qty] = float(re.sub('[^0-9\.]', '', price_str))
+            except (TypeError, AttributeError, ValueError, IndexError):
+                continue
+    except AttributeError:
+        # This happens when no pricing info is found in the tree.
+        logger.log(DEBUG_OBSESSIVE, 'No TME pricing information found!')
+        return price_tiers  # Return empty price tiers.
+    return price_tiers
+
+
+def get_part_num(html_tree):
+    '''Get the part number from the TME product page.'''
+    try:
+        return html_tree.find('td', class_="pip-product-symbol").text
+    except AttributeError:
+        logger.log(DEBUG_OBSESSIVE, 'No TME part number found!')
+        return ''
+
+
+def get_qty_avail(html_tree):
+    '''Get the available quantity of the part from the TME product page.'''
+    pn = get_part_num(html_tree)
+    if pn == '':
+        logger.log(DEBUG_OBSESSIVE, 'No TME part quantity found!')
+        return None
+
+    ajax_tree, qty_str = __ajax_details(pn)
+    if qty_str is None:
+        return None
+
+    try:
+        return int(qty_str)
+    except ValueError:
+        # No quantity found (not even 0) so this is probably a non-stocked part.
+        # Return None so the part won't show in the spreadsheet for this dist.
+        logger.log(DEBUG_OBSESSIVE, 'No TME part quantity found!')
+        return None
+
+
+def get_part_html_tree(dist, pn, extra_search_terms='', url=None, descend=2, local_part_html=None):
+    '''Find the TME HTML page for a part number and return the URL and parse tree.'''
+
+    # Use the part number to lookup the part using the site search function, unless a starting url was given.
+    if url is None:
+        url = 'http://www.tme.eu/en/katalog/?search=' + urlquote(
+            pn + ' ' + extra_search_terms,
+            safe='')
+    elif url[0] == '/':
+        url = 'http://www.tme.eu' + url
+
+    # Open the URL, read the HTML from it, and parse it into a tree structure.
+    req = FakeBrowser(url)
+    for _ in range(HTML_RESPONSE_RETRIES):
+        try:
+            response = urlopen(req)
+            html = response.read()
+            break
+        except WEB_SCRAPE_EXCEPTIONS:
+            logger.log(DEBUG_DETAILED,'Exception while web-scraping {} from {}'.format(pn, dist))
+            pass
+    else: # Couldn't get a good read from the website.
+        logger.log(DEBUG_OBSESSIVE,'No HTML page for {} from {}'.format(pn, dist))
+        raise PartHtmlError
+
+    # Abort if the part number isn't in the HTML somewhere.
+    # (Only use the numbers and letters to compare PN to HTML.)
+    if re.sub('[\W_]','',str.lower(pn)) not in re.sub('[\W_]','',str.lower(str(html))):
+        logger.log(DEBUG_OBSESSIVE,'No part number {} in HTML page from {} ({})'.format(pn, dist, url))
+        raise PartHtmlError
+
+    try:
+        tree = BeautifulSoup(html, 'lxml')
+    except Exception:
+        logger.log(DEBUG_OBSESSIVE,'No HTML tree for {} from {}'.format(pn, dist))
+        raise PartHtmlError
+
+    # If the tree contains the tag for a product page, then just return it.
+    if tree.find('div', id='ph') is not None:
+        return tree, url
+
+    # If the tree is for a list of products, then examine the links to try to find the part number.
+    if tree.find('table', id="products") is not None:
+        logger.log(DEBUG_OBSESSIVE,'Found product table for {} from {}'.format(pn, dist))
+        if descend <= 0:
+            logger.log(DEBUG_OBSESSIVE,'Passed descent limit for {} from {}'.format(pn, dist))
+            raise PartHtmlError
+        else:
+            # Look for the table of products.
+            products = tree.find(
+                'table',
+                id="products").find_all(
+                    'tr',
+                    class_=('product-row'))
+
+            # Extract the product links for the part numbers from the table.
+            product_links = []
+            for p in products:
+                for a in p.find('div', class_='manufacturer').find_all('a'):
+                    product_links.append(a)
+
+            # Extract all the part numbers from the text portion of the links.
+            part_numbers = [l.text for l in product_links]
+
+            # Look for the part number in the list that most closely matches the requested part number.
+            match = difflib.get_close_matches(pn, part_numbers, 1, 0.0)[0]
+
+            # Now look for the link that goes with the closest matching part number.
+            for l in product_links:
+                if (not l['href'].startswith('./katalog')) and l.text == match:
+                    # Get the tree for the linked-to page and return that.
+                    logger.log(DEBUG_OBSESSIVE,'Selecting {} from product table for {} from {}'.format(l.text, pn, dist))
+                    # TODO: The current implementation does up to four HTTP
+                    # requests per part (search, part details page for TME P/N,
+                    # XHR for pricing information, and XHR for stock
+                    # availability). This is mainly for the compatibility with
+                    # other distributor implementations (html_tree gets passed
+                    # to all functions).
+                    # A modified implementation (which would pass JSON data
+                    # obtained by the XHR instead of the HTML DOM tree) might be
+                    # able to do the same with just two requests (search for TME
+                    # P/N, XHR for pricing and stock availability).
+                    return get_part_html_tree(dist, pn, extra_search_terms,
+                                              url=l['href'], descend=descend-1)
+
+    # I don't know what happened here, so give up.
+    logger.log(DEBUG_OBSESSIVE,'Unknown error for {} from {}'.format(pn, dist))
+    raise PartHtmlError