def evaluate_row(action, row_idx):
"""
Given an action and a row index, evaluate the content of the action for
that index. The evaluation depends on the action type.
Given an action object and a row index:
1) Access the attached workflow
2) Obtain the row of data from the appropriate data frame
3) Process further depending on the type of action
:param action: Action object
:param row_idx: Row index to use for evaluation
:return HTML content resulting from the evaluation
"""
# Step 1: Get the workflow to access the data. No need to check for
# locking information as it has been checked upstream.
workflow = Workflow.objects.get(pk=action.workflow.id)
# Step 2: Get the row of data from the DB
try:
cond_filter = Condition.objects.get(action__id=action.id,
is_filter=True)
except ObjectDoesNotExist:
cond_filter = None
# If row_idx is an integer, get the data by index, otherwise, by key
if isinstance(row_idx, int):
row_values = ops.get_table_row_by_index(workflow,
cond_filter,
row_idx)
else:
row_values = pandas_db.get_table_row_by_key(workflow,
cond_filter,
row_idx)
if row_values is None:
# No rows satisfy the given condition
return None
# Invoke the appropriate function depending on the action type
if action.is_out:
return evaluate_row_out(action, row_values)
return evaluate_row_in(action, row_values)
def get_row_values(action, row_idx):
"""
Given an action and a row index, obtain the appropriate row of values
from the data frame.
:param action: Action object
:param row_idx: Row index to use for evaluation
:return Dictionary with the data row
"""
# Step 1: Get the row of data from the DB
cond_filter = action.get_filter()
# If row_idx is an integer, get the data by index, otherwise, by key
if isinstance(row_idx, int):
result = ops.get_table_row_by_index(action.workflow, cond_filter,
row_idx)
else:
result = pandas_db.get_table_row_by_key(action.workflow, cond_filter,
row_idx)
return result
def evaluate_row(action, row_idx):
"""
Given an action object and a row index:
1) Access the attached workflow
2) Obtain the row of data from the appropriate data frame
3) Evaluate the conditions with respect to the values in the row
4) Create a context with the result of evaluating the conditions,
attributes and column names to values
5) Run the template with the context
6) Return the resulting object (HTML?)
:param action: Action object with pointers to conditions, filter,
workflow, etc.
:param row_idx: Either an integer (row index), or a pair key=value to
filter
:return: None to flag an error
"""
# Step 1: Get the workflow to access the data. No need to check for
# locking information as it has been checked upstream.
workflow = Workflow.objects.get(pk=action.workflow.id)
# Step 2: Get the row of data from the DB
try:
cond_filter = Condition.objects.get(action__id=action.id,
is_filter=True)
except ObjectDoesNotExist:
cond_filter = None
# If row_idx is an integer, get the data by index, otherwise, by key
if isinstance(row_idx, int):
row_values = ops.get_table_row_by_index(workflow, cond_filter, row_idx)
else:
row_values = pandas_db.get_table_row_by_key(workflow, cond_filter,
row_idx)
if row_values is None:
# No rows satisfy the given condition
return None
# Step 3: Evaluate all the conditions
condition_eval = {}
condition_anomalies = []
for condition in Condition.objects.filter(action__id=action.id).values(
'name', 'is_filter', 'formula'):
if condition['is_filter']:
# Filter can be skipped in this stage
continue
# Evaluate the condition
try:
condition_eval[condition['name']] = \
dataops.formula_evaluation.evaluate_top_node(
condition['formula'],
row_values
)
except OntaskException as e:
condition_anomalies.append(e.value)
# If any of the variables was incorrectly evaluated, we replace the
# content and replace it by something noting this anomaly
if condition_anomalies:
return render_to_string('action/incorrect_preview.html',
{'missing_values': condition_anomalies})
# Step 4: Create the context with the attributes, the evaluation of the
# conditions and the values of the columns.
attributes = workflow.attributes
context = dict(dict(row_values, **condition_eval), **attributes)
# Step 5: run the template with the given context
# First create the template with the string stored in the action
try:
result = render_template(action.content, context, action)
except TemplateSyntaxError as e:
return render_to_string('action/syntax_error.html', {'msg': e.message})
# Render the text
return result