README

   1 eccc_to_commons - Set of tools to replicate
   2                   Environment and Climate change Canada data on
   3                   Wikimedia Commons
   4
   5 This is a collection of scripts (mainly Bash and XSD/XSLT).
   6
   7 Most of them use standard Unix/GNU tools so it should work on any recent GNU
   8 distribution. In addition to coreutils, prerequisites are:
   9
  10 - Bash 4+
  11 - Curl
  12 - Xmlstarlet
  13 - Jq
  14
  15 This repository is sponsored by Environment and Climate change Canada and
  16 Wikimedia Canada.
  17
  18
  19 Provided scripts, ordered by chronological usage:
  20 dllist.sh                 outputs a curl configuration file listing all available
  21                           ECCC data
  22 eccc_fixer.sh             fix upstream data XML files
  23 eccc_fixer.xslt           fix upstream data XML file
  24 commons_rules.xsd         validate ECCC XML from a Wikimedian point of view
  25 eccc_to_commons.sh        transform ECCC XML files into JSON
  26 monthly_to_commons.xslt   transform ECCC monthly XML file into JSON
  27 almanac_to_commons.xslt   transform ECCC almanac XML file into JSON
  28
  29
  30 Usage:
  31 The general idea of a large scale data import process is:
  32  1. Download a copy of all data required for the import
  33  2. Validate the cache
  34  3. Transform data into the target format
  35  4. Upload to the destination
  36
  37 These tools require some technical knowledge prior to using them so they aren't
  38 for general use. This is however a good starting point to discover how large
  39 imports are processed in community driven projects.
  40
  41
  42 In practice:
  43 Beside a reasonable amount of available disk space, you will have to create two
  44 distinct folders: the first will contain a copy of ECCC downloaded data while
  45 the second will contain the data to be uploaded to Wikimedia Commons.
  46 The following section will refer to them as ${ECCC_CACHE} and ${COMMONS_CACHE}.
  47 These environment variables must be set or replaced by valid paths when the
  48 commands are used.
  49
  50
  51 1.  Download a copy of all data required for the import
  52 1.1 Create a list of all ECCC provided files
  53 First, we generate a list of all the historical data provided by ECCC.
  54
  55  $ ./dllist.sh "${ECCC_CACHE}" > "downloads_all"
  56
  57 Expect quite long runtime. As of January 2020, it generates a list with almost
  58 650,000 download links.
  59
  60
  61 1.2 Filter unwanted files
  62 This long list may contain more files than you actually need, so you may want to
  63 reduce it so you don't have to download/store useless content.
  64 This step basically depends on your own needs, so not all cases will be covered
  65 here. downloads_all is a regular text file, so you can edit it with regular
  66 tools like sed, grep or your prefered interactive editor.
  67
  68 Here are a few examples to inspire you:
  69
  70 Keep only monthly data:
  71   $ cat downloads_all | grep -B1 -A1 --no-group-separator \
  72     -E '^output = ".*/monthly/[A-Z0-9]{7}.xml"$' > downloads_monthly
  73
  74 Remove all downloads before (restart interrupted download):
  75         $ sed -n '/https:\/\/climate.weather.gc.ca\/climate_data\/bulk_data_e.html?format=xml&timeframe=3&stationID=2606/,$p' \
  76           downloads_all > download_continue
  77
  78
  79 1.3 Download wanted files
  80 Give your own list of downloads to curl. You can add the parameters you need.
  81
  82   $ curl --fail-early --create-dirs -K download_all
  83
  84
  85 2 Fix the files
  86 Be aware the files you've downloaded is buggy. Yes, all of them, they're
  87 distributed as it by ECCC. But wait, there is a simple fix.
  88
  89 The clean way to perform the fix is to use the following script:
  90
  91   $ ./eccc_fixer.sh "${ECCC_CACHE}" "${ECCC_CACHE}-fixed"
  92
  93
  94 However, if you don't want to keep the original files, you can just do:
  95
  96   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec sed -i -e \
  97     's/xsd:schemaLocation/xsi:schemaLocation/;s/xmlns:xsd="http:\/\/www.w3.org\/TR\/xmlschema-1\/"/xmlns:xsi="http:\/\/www.w3.org\/2001\/XMLSchema-instance"/' {} +
  98
  99 From now on, the guide expects "${ECCC_CACHE}" to point the directory with fixed
 100 files only.
 101
 102
 103 3.  Validate the cache
 104 It's important you make the effort to validate the files before processing them.
 105 Every transformation makes assumptions on data structure/content that can only
 106 be asserted by using proper validation schemes. Bypassing this step may lead to
 107 not working transformations or invalid final data.
 108 This step is split in two: first we have to check the data is valid from an ECCC
 109 point of view and then we check it's valid through Wikimedian eyes.
 110
 111 3.1 Validate the data according to ECCC standards
 112 However, the XML schema distributed by ECCC is incorrect. It won't validate any XML
 113 coming from them. A fixed version can be found on Wikimedia Canada Git
 114 repositories.
 115
 116   $ git clone https://git.wikimedia.ca/eccc_schema.git
 117   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec xmlstarlet val -b \
 118     -s eccc_schema/bulkschema.xsd {} \;
 119
 120 The second command will list all incorrect files. If output is empty, you can
 121 continue.
 122
 123
 124 3.2 Validate the data according to Wikimedia standards
 125
 126   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec xmlstarlet val -b \
 127     -s commons_rules.xsd {} \;
 128
 129 Same as previously, the output should be empty. Otherwise, you must resolve
 130 every single problem before continuing.
 131
 132
 133 4. Transform data into target format
 134 Here we are, here is the fun part: let's create weather data in Wikimedia
 135 Commons format.
 136
 137   $ ./eccc_to_commons "${ECCC_CACHE}" "${COMMONS_CACHE}" 2>log
 138
 139 It will replicate the future Commons content paths inside nested directories.
 140 So, for example future
 141 https://commons.wikimedia.org/wiki/Data:weather.gc.ca/Monthly/4271.tab resource
 142 will be created in ${COMMONS_CACHE}/weather.gc.ca/Monthly/4271.tab.
 143 A sum up log file is created for further reference on what has been done during
 144 conversion.
 145
 146
 147 5. Upload to destination
 148 Not done yet.