download and load a complete stackexchange project

using the '-s' switch, download the compressed file from _https://ia800107.us.archive.org/27/items/stackexchange/_, then, uncompress it and load all the files in the database. Add a '-n' switch to move the tables to a given schema

WARNING: since using the urllib.request module, set the script to use python3

Author: madtibo

README.md

@@ -18,14 +18,14 @@ Schema hints are taken from [a post on Meta.StackExchange](http://meta.stackexch
    `Badges.xml`, `Votes.xml`, `Posts.xml`, `Users.xml`, `Tags.xml`.
    - In some old dumps, the cases in the filenames are different.
  - Execute in the current folder (in parallel, if desired):
-   - `python load_into_pg.py Badges`
-   - `python load_into_pg.py Posts`
-   - `python load_into_pg.py Tags` (not present in earliest dumps)
-   - `python load_into_pg.py Users`
-   - `python load_into_pg.py Votes`
-   - `python load_into_pg.py PostLinks`
-   - `python load_into_pg.py PostHistory`
-   - `python load_into_pg.py Comments`
+   - `python load_into_pg.py -t Badges`
+   - `python load_into_pg.py -t Posts`
+   - `python load_into_pg.py -t Tags` (not present in earliest dumps)
+   - `python load_into_pg.py -t Users`
+   - `python load_into_pg.py -t Votes`
+   - `python load_into_pg.py -t PostLinks`
+   - `python load_into_pg.py -t PostHistory`
+   - `python load_into_pg.py -t Comments`
  - Finally, after all the initial tables have been created:
    - `psql stackoverflow < ./sql/final_post.sql`
    - If you used a different database name, make sure to use that instead of
@@ -34,7 +34,25 @@ Schema hints are taken from [a post on Meta.StackExchange](http://meta.stackexch
    - `psql stackoverflow < ./sql/optional_post.sql`
    - Again, remember to user the correct database name here, if not `stackoverflow`.
 
-## Caveats
+## Loading a complete stackexchange project
+
+You can use the script to download a given stackexchange compressed file from
+[archive.org](https://ia800107.us.archive.org/27/items/stackexchange/) and load
+all the tables at once, using the `-s` switch.
+
+You will need the `urllib` and `libarchive` modules.
+
+If you give a schema name using the `-n` switch, all the tables will be moved
+to the given schema. This schema will be created in the script.
+
+To load the _dba.stackexchange.com_ project in the `dba` schema, you would execute:
+`./load_into_pg.py -s dba -n dba`
+
+The paths are not changed in the final scripts `sql/final_post.sql` and
+`sql/optional_post.sql`. To run them, first set the _search_path_ to your
+schema name: `SET search_path TO <myschema>;`
+
+## Caveats and TODOs
 
  - It prepares some indexes and views which may not be necessary for your analysis.
  - The `Body` field in `Posts` table is NOT populated by default. You have to use `--with-post-body` argument to include it.

load_into_pg.py

@@ -1,8 +1,9 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import sys
 import time
 import argparse
 import psycopg2 as pg
+import os
 import row_processor as Processor
 import six
 import json
@@ -12,6 +13,51 @@
     ('Posts', 'ViewCount'): "NULLIF(%(ViewCount)s, '')::int"
 }
 
+# part of the file already downloaded
+file_part = None
+
+def show_progress(block_num, block_size, total_size):
+    """Display the total size of the file to download and the progess in percent"""
+    global file_part
+    if file_part is None:
+        suffixes=['B','KB','MB','GB','TB']
+        suffixIndex = 0
+        pp_size = total_size
+        while pp_size > 1024:
+            suffixIndex += 1 #increment the index of the suffix
+            pp_size = pp_size/1024.0 #apply the division
+        six.print_('Total file size is: {0:.1f} {1}'.format(pp_size,suffixes[suffixIndex]))
+        six.print_("0 % of the file downloaded ...\r", end="", flush=True)
+        file_part = 0
+
+    downloaded = block_num * block_size
+    if downloaded < total_size:
+        percent = 100 * downloaded / total_size
+        if percent - file_part > 1:
+            file_part = percent
+            six.print_("{0} % of the file downloaded ...\r".format(int(percent)), end="", flush=True)
+    else:
+        file_part = None
+        six.print_("")
+
+def buildConnectionString(dbname, mbHost, mbPort, mbUsername, mbPassword):
+    dbConnectionParam = "dbname={}".format(dbname)
+
+    if mbPort is not None:
+        dbConnectionParam += ' port={}'.format(mbPort)
+
+    if mbHost is not None:
+        dbConnectionParam += ' host={}'.format(mbHost)
+
+    # TODO Is the escaping done here correct?
+    if mbUsername is not None:
+        dbConnectionParam += ' user={}'.format(mbUsername)
+
+    # TODO Is the escaping done here correct?
+    if mbPassword is not None:
+        dbConnectionParam += ' password={}'.format(mbPassword)
+    return dbConnectionParam
+
 def _makeDefValues(keys):
     """Returns a dictionary containing None for all keys."""
     return dict(( (k, None) for k in keys ))
@@ -150,7 +196,7 @@ def _getTableKeys(table):
         ]
     return keys
 
-def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, mbUsername, mbPassword):
+def handleTable(table, insertJson, createFk, mbDbFile, dbConnectionParam):
     """Handle the table including the post/pre processing."""
     keys       = _getTableKeys(table)
     dbFile     = mbDbFile if mbDbFile is not None else table + '.xml'
@@ -165,23 +211,6 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
         six.print_("Could not load pre/post/fk sql. Are you running from the correct path?", file=sys.stderr)
         sys.exit(-1)
 
-    dbConnectionParam = "dbname={}".format(dbname)
-
-    if mbPort is not None:
-        dbConnectionParam += ' port={}'.format(mbPort)
-
-    if mbHost is not None:
-        dbConnectionParam += ' host={}'.format(mbHost)
-
-    # TODO Is the escaping done here correct?
-    if mbUsername is not None:
-        dbConnectionParam += ' user={}'.format(mbUsername)
-
-    # TODO Is the escaping done here correct?
-    if mbPassword is not None:
-        dbConnectionParam += ' password={}'.format(mbPassword)
-
-
     try:
         with pg.connect(dbConnectionParam) as conn:
             with conn.cursor() as cur:
@@ -208,7 +237,7 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
                                       ' VALUES\n' + valuesStr + ';'
                                 cur.execute(cmd)
                                 conn.commit()
-                        six.print_('Table {0} processing took {1:.1f} seconds'.format(table, time.time() - start_time))
+                        six.print_('Table \'{0}\' processing took {1:.1f} seconds'.format(table, time.time() - start_time))
 
                         # Post-processing (creation of indexes)
                         start_time = time.time()
@@ -237,12 +266,32 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
         six.print_("Warning from the database.", file=sys.stderr)
         six.print_("pg.Warning: {0}".format(str(w)), file=sys.stderr)
 
+
+def moveTableToSchema(table, schemaName, dbConnectionParam):
+    try:
+        with pg.connect(dbConnectionParam) as conn:
+            with conn.cursor() as cur:
+                # create the schema
+                cur.execute('CREATE SCHEMA IF NOT EXISTS '+schemaName+';')
+                conn.commit()
+                # move the table to the right schema
+                cur.execute('ALTER TABLE '+table+' SET SCHEMA '+schemaName+';')
+                conn.commit()
+    except pg.Error as e:
+        six.print_("Error in dealing with the database.", file=sys.stderr)
+        six.print_("pg.Error ({0}): {1}".format(e.pgcode, e.pgerror), file=sys.stderr)
+        six.print_(str(e), file=sys.stderr)
+    except pg.Warning as w:
+        six.print_("Warning from the database.", file=sys.stderr)
+        six.print_("pg.Warning: {0}".format(str(w)), file=sys.stderr)
+
 #############################################################
 
 parser = argparse.ArgumentParser()
-parser.add_argument( 'table'
+parser.add_argument( '-t', '--table'
                    , help    = 'The table to work on.'
                    , choices = ['Users', 'Badges', 'Posts', 'Tags', 'Votes', 'PostLinks', 'PostHistory', 'Comments']
+                   , default = None
                    )
 
 parser.add_argument( '-d', '--dbname'
@@ -255,6 +304,22 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
                    , default = None
                    )
 
+parser.add_argument( '-s', '--so-project'
+                   , help    = 'stackexchange project to load.'
+                   , default = None
+                   )
+
+parser.add_argument( '--archive-url'
+                   , help    = 'URL of the archive directory to retrieve.'
+                   , default = 'https://ia800107.us.archive.org/27/items/stackexchange'
+                   )
+
+parser.add_argument( '-k', '--keep-archive'
+                   , help    = 'should we keep the downloaded archive.'
+                   , action = 'store_true'
+                   , default = False
+                   )
+
 parser.add_argument( '-u', '--username'
                    , help    = 'Username for the database.'
                    , default = None
@@ -287,6 +352,11 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
                    , default = False
                    )
 
+parser.add_argument( '-n', '--schema-name'
+                   , help    = 'Use specific schema.'
+                   , default = 'public'
+                   )
+
 parser.add_argument( '--foreign-keys'
                    , help    = 'Create foreign keys.'
                    , action = 'store_true'
@@ -295,22 +365,71 @@ def handleTable(table, insertJson, createFk, dbname, mbDbFile, mbHost, mbPort, m
 
 args = parser.parse_args()
 
-table = args.table
-
 try:
     # Python 2/3 compatibility
     input = raw_input
 except NameError:
     pass
 
+dbConnectionParam = buildConnectionString(args.dbname, args.host, args.port, args.username, args.password)
+
+# load given file in table
+if args.file and args.table:
+    table = args.table
+
+    if table == 'Posts':
+        # If the user has not explicitly asked for loading the body, we replace it with NULL
+        if not args.with_post_body:
+            specialRules[('Posts', 'Body')] = 'NULL'
+
+    choice = input('This will drop the {} table. Are you sure [y/n]?'.format(table))
+    if len(choice) > 0 and choice[0].lower() == 'y':
+        handleTable(table, args.insert_json, args.foreign_keys, args.file, dbConnectionParam)
+    else:
+        six.print_("Cancelled.")
+    if args.schema_name != 'public':
+        moveTableToSchema(table, args.schema_name, dbConnectionParam)
+    exit(0)
+
+# load a project
+elif args.so_project:
+    import urllib.request
+    import libarchive
+
+    # download the 7z archive in /tmp
+    file_name = args.so_project + '.stackexchange.com.7z'
+    url = '{0}/{1}'.format(args.archive_url, file_name)
+    filepath = '/tmp/'+file_name
+    six.print_('Downloading the archive, please be patient ...')
+    try:
+        urllib.request.urlretrieve(url, filepath, show_progress)
+    except Exception as e:
+        six.print_('Error: impossible to download the {0} archive ({1})'.format(url, e))
+        exit(1)
+
+    try:
+        libarchive.extract_file(filepath)
+    except Exception as e:
+        six.print_('Error: impossible to extract the {0} archive ({1})'.format(url, e))
+        exit(1)
+
+    tables = [ 'Tags', 'Users', 'Badges', 'Posts', 'Comments', 'Votes', 'PostLinks', 'PostHistory' ]
+
+    for table in tables:
+        six.print_('Load {0}.xml file'.format(table))
+        handleTable(table, args.insert_json, args.foreign_keys, args.file, dbConnectionParam)
+        # remove file
+        os.remove(table+'.xml')
+
+    if not args.keep_archive:
+        # remove archive
+        os.remove(filepath)
 
-if table == 'Posts':
-    # If the user has not explicitly asked for loading the body, we replace it with NULL
-    if not args.with_post_body:
-        specialRules[('Posts', 'Body')] = 'NULL'
+    if args.schema_name != 'public':
+        for table in tables:
+            moveTableToSchema(table, args.schema_name, dbConnectionParam)
+    exit(0)
 
-choice = input('This will drop the {} table. Are you sure [y/n]? '.format(table))
-if len(choice) > 0 and choice[0].lower() == 'y':
-    handleTable(table, args.insert_json, args.foreign_keys, args.dbname, args.file, args.host, args.port, args.username, args.password)
 else:
-    six.print_("Cancelled.")
+    six.print_("Error: you must either use '-f' and '-t'  arguments or the '-s' argument.")
+    parser.print_help()

sql/Votes_pre.sql

@@ -1,7 +1,7 @@
 DROP TABLE IF EXISTS Votes CASCADE;
 CREATE TABLE Votes (
    Id                int         PRIMARY KEY ,
-   PostId            int         not NULL    ,
+   PostId            int         , -- not NULL    ,
    VoteTypeId        int         not NULL    ,
    UserId            int                     ,
    CreationDate      timestamp   not NULL    ,