I am developing a web application using django. I am new Django.
I have call a stored procedure from my application. I gone through the django documentation and i found out that using cursor object i can call the procedure. But i cannot find the cursor object in connection object.
This is how my code looks like :
from django.db import connection
cursor = connection.cursor()
But i cannot find cursor object itself in the connection.
Please help me out where i am going wrong.
I can't see anything wrong with the code you post, I'll assume you don't know how to proceed after you have the cursor, so this is an example:
from django.db import models
from django.db import connection
class Document(models.Model):
# fields
url = models.CharField(max_length=900)
content = models.TextField()
title = models.TextField()
# static method to perform a fulltext search
#staticmethod
def search(search_string):
# create a cursor
cur = connection.cursor()
# execute the stored procedure passing in
# search_string as a parameter
cur.callproc('searcher_document_search', [search_string,])
# grab the results
results = cur.fetchall()
cur.close()
# wrap the results up into Document domain objects
return [Document(*row) for row in results]
Related
i'm trying to make a custom plotly-graphic on a wagtail homepage.
I got this far. I'm overriding the wagtail Page-model by altering the context returned to the template. Am i doing this the right way, is this possible in models.py ?
Thnx in advanced.
from django.db import models
from wagtail.models import Page
from wagtail.fields import RichTextField
from wagtail.admin.panels import FieldPanel
import psycopg2
from psycopg2 import sql
import pandas as pd
import plotly.graph_objs as go
from plotly.offline import plot
class CasPage(Page):
body = RichTextField(blank=True)
content_panels = Page.content_panels + [
FieldPanel('body'),
]
def get_connection(self):
try:
return psycopg2.connect(
database="xxxx",
user="xxxx",
password="xxxx",
host="xxxxxxxxxxxxx",
port=xxxxx,
)
except:
return False
conn = get_connection()
cursor = conn.cursor()
strquery = (f'''SELECT t.datum, t.grwaarde - LAG(t.grwaarde,1) OVER (ORDER BY datum) AS
gebruiktgas
FROM XXX
''')
data = pd.read_sql(strquery, conn)
fig1 = go.Figure(
data = data,
layout=go.Layout(
title="Gas-verbruik",
yaxis_title="aantal M3")
)
output = plotly.plot(fig1, output_type='div', include_plotlyjs=False)
# https://stackoverflow.com/questions/32626815/wagtail-views-extra-context
def get_context(self, request):
context = super(CasPage, self).get_context(request)
context['output'] = output
return context
Kind of the right track. You should move all the plot code into its own method though. At the moment, it runs the plot code when the site initialises then stays stored in memory.
There's three usual ways to get the plot to the rendered page then.
As you've done with context
As a property or method of the page class
As a template tag called from the template
The first two have more or less the same effect, except the 2nd makes the property available anywhere, not just the template. The context method runs before the page starts rendering, the other two happen during that process. I guess the only real difference there is that if you're using template caching, the context will always run each time the page is loaded, the other two only run when the cache is invalid, or if the code is escaped out of the cache (for fragment caching).
To call the plot as a property of your page class, you'd just pull out the code into a def with the #property decorator:
class CasPage(Page):
....
#property
def plot(self):
try:
conn = psycopg2.connect(
database="xxxx",
user="xxxx",
password="xxxx",
host="xxxxxxxxxxxxx",
port=xxxxx,
)
cursor = conn.cursor()
strquery = (f'''SELECT t.datum, t.grwaarde - LAG(t.grwaarde,1) OVER (ORDER BY datum) AS
gebruiktgas FROM XXX''')
data = pd.read_sql(strquery, conn)
fig1 = go.Figure(
data = data,
layout=go.Layout(
title="Gas-verbruik",
yaxis_title="aantal M3")
)
return plotly.plot(fig1, output_type='div', include_plotlyjs=False)
except Exception as e:
print(f"{type(e).__name__} at line {e.__traceback__.tb_lineno} of {__file__}: {e}")
return None
^ I haven't tried this code ... it should work as is, but no guarantees I didn't make a typo ;)
Now you can access your plot with {{ self.plot }} in the template.
If you want to stick with context, then you'd stay with the def above but just amend your output line to
context['output'] = self.plot
Template tags are more useful when they're being used in StructBlocks and not part of a page class like this, or where you have code that you want to re-use in multiple templates.
Then you'd move all that plot code into a template tag file, register it and call it in the template with {% plot %}. Wagtail template tags work the same as Django: https://docs.djangoproject.com/en/4.1/howto/custom-template-tags/
Is the plot data outside of the site database? If not, you could probably get the data via the ORM if it was defined as a model. If so, it's probably worth writing a view (or stored procedure if you want to pass parameters) on the db server and calling that rather than hard coding the SQL into your python.
The other consideration is the page load time - if the dataset is big, this could take a while and prevent the page from loading. You'd probably want a front-end solution in that case.
while using beaker session, i came across to use same session object along the whole application.
I came through this url: Bottle.py session with Beaker
But, still i am getting 'KeyError' when i am trying to access the save session value in one function by another function.
my rest.py file looks like:
import bottle
from bottle import route,default_app
from beaker.middleware import SessionMiddleware
app = bottle.default_app()
#bottle.hook('before_request')
def setup_request():
request.session = request.environ['beaker.session']
#app.route('/login')
def login():
request.session['uname'] = 'user'
#app.route('/logout')
def logout():
print request.session['uname']
# expecting to print user
session_opts = {
'session.type': 'file',
'session.data_dir': '/tmp/',
'session.cookie_expires': True,
}
app = SessionMiddleware(bottle.default_app(),session_opts)
I have mentioned the SessionMiddleware at the end as im getting errors with the help of this link https://groups.google.com/forum/#!topic/bottlepy/m0akSbWRpZg
But when i am accessing request.session in the logout function i am getting
'KeyError': Uname not found
can any one give clear example of how to adjust the code inorder to maintain same session in whole application.
I'm building a basic blog from the Web Development course by Steve Hoffman on Udacity. This is my code -
import os
import webapp2
import jinja2
from google.appengine.ext import db
template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir), autoescape = True)
def datetimeformat(value, format='%H:%M / %d-%m-%Y'):
return value.strftime(format)
jinja_env.filters['datetimeformat'] = datetimeformat
def render_str(template, **params):
t = jinja_env.get_template(template)
return t.render(params)
class Entries(db.Model):
title = db.StringProperty(required = True)
body = db.TextProperty(required = True)
created = db.DateTimeProperty(auto_now_add = True)
class MainPage(webapp2.RequestHandler):
def get(self):
entries = db.GqlQuery('select * from Entries order by created desc limit 10')
self.response.write(render_str('mainpage.html', entries=entries))
class NewPost(webapp2.RequestHandler):
def get(self):
self.response.write(render_str('newpost.html', error=""))
def post(self):
title = self.request.get('title')
body = self.request.get('body')
if title and body:
e = Entries(title=title, body=body)
length = db.GqlQuery('select * from Entries order by created desc').count()
e.put()
self.redirect('/newpost/' + str(length+1))
else:
self.response.write(render_str('newpost.html', error="Please type in a title and some content"))
class Permalink(webapp2.RequestHandler):
def get(self, id):
e = db.GqlQuery('select * from Entries order by created desc').get()
self.response.write(render_str('permalink.html', id=id, entry = e))
app = webapp2.WSGIApplication([('/', MainPage),
('/newpost', NewPost),
('/newpost/(\d+)', Permalink)
], debug=True)
In the class Permalink, I'm using the get() method on the query than returns all records in the descending order of creation. So, it should return the most recently added record. But when I try to add a new record, permalink.html (it's just a page with shows the title, the body and the date of creation of the new entry) shows the SECOND most recently added. For example, I already had three records, so when I added a fourth record, instead of showing the details of the fourth record, permalink.html showed me the details of the third record. Am I doing something wrong?
I don't think my question is a duplicate of this - Read delay in App Engine Datastore after put(). That question is about read delay of put(), while I'm using get(). The accepted answer also states that get() doesn't cause any delay.
This is because of eventual consistency used by default for GQL queries.
You need to read:
https://cloud.google.com/appengine/docs/python/datastore/data-consistency
https://cloud.google.com/appengine/docs/python/datastore/structuring_for_strong_consistency
https://cloud.google.com/datastore/docs/articles/balancing-strong-and-eventual-consistency-with-google-cloud-datastore/
search & read on SO and other source about strong & eventual consistency in Google Cloud Datastore.
You can specify read_policy=STRONG_CONSISTENCY for your query but it has associated costs that you should be aware of and take into account.
I have two models,Foto and FotoMetadata. Foto just has one property called upload, that is an upload field. FotoMetadata has a few properties and should receive metadata from the foto uploaded at Foto. This can be done manually at the admin interface, but I want to do it automatically, i.e: when a photo is uploaded through admin interface, the FotoMetadata is automatically filled.
In my model.py I have a few classes, including Foto and FotoMetadata:
class Foto(models.Model):
upload = models.FileField(upload_to="fotos")
def __str__(self):
return '%s' %(self.upload)
class FotoMetadata(models.Model):
image_formats = (
('RAW', 'RAW'),
('JPG', 'JPG'),
)
date = models.DateTimeField()
camera = models.ForeignKey(Camera, on_delete=models.PROTECT)
format = models.CharField(max_length=8, choices=image_formats)
exposure = models.CharField(max_length=8)
fnumber = models.CharField(max_length=8)
iso = models.IntegerField()
foto = models.OneToOneField(
Foto,
on_delete=models.CASCADE,
primary_key=True,
)
When I login at the admin site, I have an upload form related to the Foto, and this is working fine. My problem is that I can't insert metadata at FotoMetadata on the go. I made a function that parse the photo and give me a dictionary with the info I need. This function is called GetExif is at a file called getexif.py. This will be a simplified version of it:
def GetExif(foto):
# Open image file for reading (binary mode)
f = open(foto, 'rb')
# Parse file
...
<parsing code>
...
f.close()
#create dictionary to receive data
meta={}
meta['date'] = str(tags['EXIF DateTimeOriginal'].values)
meta['fnumber'] = str(tags['EXIF FNumber'])
meta['exposure'] = str(tags['EXIF ExposureTime'])
meta['iso'] = str(tags['EXIF ISOSpeedRatings'])
meta['camera'] =str( tags['Image Model'].values)
return meta
So, basically, what I'm trying to do is use this function at admin.py to automatically populate the FotoMetadata when uploading a photo at Foto, but I really couldn't figure out how to make it. Does any one have a clue?
Edit 24/03/2016
Ok, after a lot more failures, I'm trying to use save_model in admin.py:
from django.contrib import admin
from .models import Autor, Camera, Lente, Foto, FotoMetadata
from fotomanager.local.getexif import GetExif
admin.site.register(Autor)
admin.site.register(Camera)
admin.site.register(Lente)
admin.site.register(FotoMetadata)
class FotoAdmin(admin.ModelAdmin):
def save_model(self, request, obj, form, change):
# populate the model
obj.save()
# get metadata
metadados = GetExif(obj.upload.url)
# Create instance of FotoMetadata
fotometa = FotoMetadata()
# FotoMetadata.id = Foto.id
fotometa.foto = obj.pk
# save exposure
fotometa.exposure = metadados['exposure']
admin.site.register(Foto, FotoAdmin)
I thought it would work, or that I will have problems saving data to the model, but actually I got stucked before this. I got this error:
Exception Type: FileNotFoundError
Exception Value:
[Errno 2] No such file or directory: 'http://127.0.0.1:8000/media/fotos/IMG_8628.CR2'
Exception Location: /home/ricardo/Desenvolvimento/fotosite/fotomanager/local/getexif.py in GetExif, line 24
My GetExif function can't read the file, however, the file path is right! If I copy and paste it to my browser, it downloads the file. I'm trying to figure out a way to correct the address, or to pass the internal path, or to pass the real file to the function instead of its path. I'm also thinking about a diferent way to access the file at GetExif() function too. Any idea of how to solve it?
Solution
I solved the problem above! By reading the FileField source, I've found a property called path, which solve the problem. I also made a few other modifications and the code is working. The class FotoAdmin, at admin.py is like this now:
class FotoAdmin(admin.ModelAdmin):
def save_model(self, request, obj, form, change):
# populate the model
obj.save()
# get metadata
metadados = GetExif(obj.upload.path)
# Create instance of FotoMetadata
fotometa = FotoMetadata()
# FotoMetadata.id = Foto.id
fotometa.foto = obj
# set and save exposure
fotometa.exposure = metadados['exposure']
fotometa.save()
I also had to set null=True at some properties in models.py and everything is working as it should.
I guess you want to enable post_save a signal
read : django signals
Activate the post_save signal - so after you save a FOTO you have a hook to do other stuff, in your case parse photometa and create a FotoMetadata instance.
More, if you want to save the foto only if fotometa succeed , or any other condition you may use , pre_save signal and save the foto only after meta foto was saved.
Hi all reportlab master,
I've search the web and also here in stackoverflow but can't find a similar situation on my problem I'm trying to solve during this Holiday vacation.
In django admin, I'm trying to create an action to view my database to a specific format. If I select one record I can view the report in one page pdf. Which is fine. In case the user try to more record that's where the problem start. For example I select multiple record, I can view the report but all content is still in one page pdf.
Is there a way to show a record per page in pdf? All reportlab master jedi, Please help me how to do this the right way.
Here's my code on what I did.
from django.contrib import admin
from models import LatestRsl
from io import BytesIO
from reportlab.pdfgen import canvas
from django.http import HttpResponse
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from reportlab.lib.units import inch
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.platypus import BaseDocTemplate, PageTemplate, Paragraph, Frame
from reportlab.lib.pagesizes import letter
def go(modeladmin, request, queryset):
response = HttpResponse(mimetype='application/pdf')
response['Content-Disposition'] = 'filename = testframe.pdf'
buffer = StringIO()
c = canvas.Canvas(buffer)
doc = BaseDocTemplate(buffer, showBoundary=1, leftMargin= 0.1*inch, rightMargin= 0.1*inch,
topMargin= 0.1*inch, bottomMargin= 0.1*inch)
signfr = Frame(5.1*inch, 1.2*inch, 2.8*inch, 0.44*inch, showBoundary=1)
modelfr = Frame(3.6*inch, 4.6*inch, 2.8*inch, 0.44*inch, showBoundary=1)
doc.addPageTemplates([PageTemplate(id= 'rsl_frame', frames=[signfr, modelfr]),
PageTemplate(id= 'rsl_frame2', frames=[signfr, modelfr])])
story = []
styles=getSampleStyleSheet()
styles.add(ParagraphStyle(name='Verdana9', fontName= 'Verdana', fontSize= 9))
styles.add(ParagraphStyle(name='VerdanaB10', fontName= 'VerdanaB', fontSize= 10))
for obj in queryset:
#1st frame
model = Paragraph(obj.make,styles["Verdana9"])
story.append(model)
modelfr.addFromList(story,c)
#2nd frame
signatory = Paragraph(obj.signatory,styles["VerdanaB10"])
story.append(signatory)
signfr.addFromList(story,c)
doc.build(story)
c.showPage()
c.save()
pdf = buffer.getvalue()
buffer.close()
response.write(pdf)
return response
Assuming your queryset variable contains all the records you need, you could insert a PageBreak object. Just add from reportlab.platypus import PageBreak to the top of your file, then append a PageBreak object to your document's elements.
If you want to change the template for each page, you can also append a NextPageTemplate and pass the id of your PageTemplate. You'll need to add from reportlab.platypus import NextPageTemplate to the top of your file as well.
for obj in queryset:
#1st frame
model = Paragraph(obj.make,styles["Verdana9"])
story.append(model)
modelfr.addFromList(story,c)
#2nd frame
signatory = Paragraph(obj.signatory,styles["VerdanaB10"])
story.append(signatory)
signfr.addFromList(story,c)
# Force the report to use a different PageTemplate on the next page
story.append(NextPageTemplate('rsl_frame2'))
# Start a new page for the next object in the query
story.append(PageBreak())
You could move the PageBreak wherever you need it, but it's a simple "function" flowable. NextPageTemplate can take the id of any valid PageTemplate object that you've added via addPageTemplates.