Merge pull request #49 from cs50/develop

2.4.0

Author: Kareem Zidane

.travis.yml

@@ -10,11 +10,13 @@ services:
 install:
 - python setup.py install
 - pip install mysqlclient
-- pip install psycopg2
+- pip install psycopg2-binary
 before_script:
 - mysql -e 'CREATE DATABASE IF NOT EXISTS test;'
 - psql -c 'create database test;' -U postgres
+- touch test.db
 script: python tests/sql.py
+after_script: rm -f test.db
 jobs:
   include:
   - stage: deploy

setup.py

@@ -16,5 +16,5 @@
     package_dir={"": "src"},
     packages=["cs50"],
     url="https://github.com/cs50/python-cs50",
-    version="2.3.3"
+    version="2.4.0"
 )

src/cs50/cs50.py

@@ -83,7 +83,7 @@ def get_char(prompt=None):
         if len(s) == 1:
             return s[0]
 
-        # temporarily here for backwards compatibility
+        # Temporarily here for backwards compatibility
         if prompt is None:
             print("Retry: ", end="")
 
@@ -104,7 +104,7 @@ def get_float(prompt=None):
             except ValueError:
                 pass
 
-        # temporarily here for backwards compatibility
+        # Temporarily here for backwards compatibility
         if prompt is None:
             print("Retry: ", end="")
 
@@ -122,12 +122,12 @@ def get_int(prompt=None):
         if re.search(r"^[+-]?\d+$", s):
             try:
                 i = int(s, 10)
-                if type(i) is int:  # could become long in Python 2
+                if type(i) is int:  # Could become long in Python 2
                     return i
             except ValueError:
                 pass
 
-        # temporarily here for backwards compatibility
+        # Temporarily here for backwards compatibility
         if prompt is None:
             print("Retry: ", end="")
 
@@ -149,7 +149,7 @@ def get_long(prompt=None):
                 except ValueError:
                     pass
 
-            # temporarily here for backwards compatibility
+            # Temporarily here for backwards compatibility
             if prompt is None:
                 print("Retry: ", end="")
 

src/cs50/sql.py

@@ -2,10 +2,12 @@
 import decimal
 import importlib
 import logging
+import os
 import re
 import sqlalchemy
 import sqlparse
 import sys
+import termcolor
 import warnings
 
 
@@ -22,12 +24,52 @@ def __init__(self, url, **kwargs):
         http://docs.sqlalchemy.org/en/latest/dialects/index.html
         """
 
-        # log statements to standard error
+        # Require that file already exist for SQLite
+        matches = re.search(r"^sqlite:///(.+)$", url)
+        if matches:
+            if not os.path.exists(matches.group(1)):
+                raise RuntimeError("does not exist: {}".format(matches.group(1)))
+            if not os.path.isfile(matches.group(1)):
+                raise RuntimeError("not a file: {}".format(matches.group(1)))
+
+        # Create engine, raising exception if back end's module not installed
+        self.engine = sqlalchemy.create_engine(url, **kwargs)
+
+        # Log statements to standard error
         logging.basicConfig(level=logging.DEBUG)
         self.logger = logging.getLogger("cs50")
 
-        # create engine, raising exception if back end's module not installed
-        self.engine = sqlalchemy.create_engine(url, **kwargs)
+        # Test database
+        try:
+            self.logger.disabled = True
+            self.execute("SELECT 1")
+        except sqlalchemy.exc.OperationalError as e:
+            e = RuntimeError(self._parse(e))
+            e.__cause__ = None
+            raise e
+        else:
+            self.logger.disabled = False
+
+    def _parse(self, e):
+        """Parses an exception, returns its message."""
+
+        # MySQL
+        matches = re.search(r"^\(_mysql_exceptions\.OperationalError\) \(\d+, \"(.+)\"\)$", str(e))
+        if matches:
+            return matches.group(1)
+
+        # PostgreSQL
+        matches = re.search(r"^\(psycopg2\.OperationalError\) (.+)$", str(e))
+        if matches:
+            return matches.group(1)
+
+        # SQLite
+        matches = re.search(r"^\(sqlite3\.OperationalError\) (.+)$", str(e))
+        if matches:
+            return matches.group(1)
+
+        # Default
+        return str(e)
 
     def execute(self, text, **params):
         """
@@ -81,77 +123,91 @@ def process(value):
                     elif isinstance(value, sqlalchemy.sql.elements.Null):
                         return sqlalchemy.types.NullType().literal_processor(dialect)(value)
 
-                    # unsupported value
+                    # Unsupported value
                     raise RuntimeError("unsupported value")
 
-                # process value(s), separating with commas as needed
+                # Process value(s), separating with commas as needed
                 if type(value) is list:
                     return ", ".join([process(v) for v in value])
                 else:
                     return process(value)
 
-        # allow only one statement at a time
+        # Allow only one statement at a time
         if len(sqlparse.split(text)) > 1:
             raise RuntimeError("too many statements at once")
 
-        # raise exceptions for warnings
+        # Raise exceptions for warnings
         warnings.filterwarnings("error")
 
-        # prepare, execute statement
+        # Prepare, execute statement
         try:
 
-            # construct a new TextClause clause
+            # Construct a new TextClause clause
             statement = sqlalchemy.text(text)
 
-            # iterate over parameters
+            # Iterate over parameters
             for key, value in params.items():
 
-                # translate None to NULL
+                # Translate None to NULL
                 if value is None:
                     value = sqlalchemy.sql.null()
 
-                # bind parameters before statement reaches database, so that bound parameters appear in exceptions
+                # Bind parameters before statement reaches database, so that bound parameters appear in exceptions
                 # http://docs.sqlalchemy.org/en/latest/core/sqlelement.html#sqlalchemy.sql.expression.text
                 statement = statement.bindparams(sqlalchemy.bindparam(
                     key, value=value, type_=UserDefinedType()))
 
-            # stringify bound parameters
+            # Stringify bound parameters
             # http://docs.sqlalchemy.org/en/latest/faq/sqlexpressions.html#how-do-i-render-sql-expressions-as-strings-possibly-with-bound-parameters-inlined
             statement = str(statement.compile(compile_kwargs={"literal_binds": True}))
 
-            # execute statement
-            result = self.engine.execute(statement)
+            # Statement for logging
+            log = re.sub(r"\n\s*", " ", sqlparse.format(statement, reindent=True))
 
-            # log statement
-            self.logger.debug(re.sub(r"\n\s*", " ", sqlparse.format(statement, reindent=True)))
+            # Execute statement
+            result = self.engine.execute(statement)
 
-            # if SELECT (or INSERT with RETURNING), return result set as list of dict objects
+            # If SELECT (or INSERT with RETURNING), return result set as list of dict objects
             if re.search(r"^\s*SELECT", statement, re.I):
 
-                # coerce any decimal.Decimal objects to float objects
+                # Coerce any decimal.Decimal objects to float objects
                 # https://groups.google.com/d/msg/sqlalchemy/0qXMYJvq8SA/oqtvMD9Uw-kJ
                 rows = [dict(row) for row in result.fetchall()]
                 for row in rows:
                     for column in row:
                         if isinstance(row[column], decimal.Decimal):
                             row[column] = float(row[column])
-                return rows
+                ret = rows
 
-            # if INSERT, return primary key value for a newly inserted row
+            # If INSERT, return primary key value for a newly inserted row
             elif re.search(r"^\s*INSERT", statement, re.I):
                 if self.engine.url.get_backend_name() in ["postgres", "postgresql"]:
                     result = self.engine.execute(sqlalchemy.text("SELECT LASTVAL()"))
-                    return result.first()[0]
+                    ret = result.first()[0]
                 else:
-                    return result.lastrowid
+                    ret = result.lastrowid
 
-            # if DELETE or UPDATE, return number of rows matched
+            # If DELETE or UPDATE, return number of rows matched
             elif re.search(r"^\s*(?:DELETE|UPDATE)", statement, re.I):
-                return result.rowcount
+                ret = result.rowcount
 
-            # if some other statement, return True unless exception
-            return True
+            # If some other statement, return True unless exception
+            else:
+                ret = True
 
-        # if constraint violated, return None
+        # If constraint violated, return None
         except sqlalchemy.exc.IntegrityError:
+            self.logger.debug(termcolor.colored(log, "yellow"))
             return None
+
+        # If user errror
+        except sqlalchemy.exc.OperationalError as e:
+            self.logger.debug(termcolor.colored(log, "red"))
+            e = RuntimeError(self._parse(e))
+            e.__cause__ = None
+            raise e
+
+        # Return value
+        else:
+            self.logger.debug(termcolor.colored(log, "green"))
+            return ret

tests/flask/application.py

@@ -1,6 +1,9 @@
 import requests
+import sys
 from flask import Flask, render_template
 
+sys.path.insert(0, "../../src")
+
 import cs50
 
 app = Flask(__name__)

tests/mysql.py

@@ -0,0 +1,8 @@
+import sys
+
+sys.path.insert(0, "../src")
+
+from cs50 import SQL
+
+db = SQL("mysql://root@localhost/test")
+db.execute("SELECT 1")

tests/sqlite.py

@@ -1,3 +1,7 @@
+import sys
+
+sys.path.insert(0, "../src")
+
 from cs50 import SQL
 
 db = SQL("sqlite:///sqlite.db")

tests/tb.py

@@ -1,3 +1,7 @@
+import sys
+
+sys.path.insert(0, "../src")
+
 import cs50
 import requests