I am planning to create a web app that allows users to downgrade their visual studio project files. However, It seems Google App Engine accepts files uploading and flat file storing on the Google Server through db.TextProperty and db.BlobProperty.
I'll be glad anyone can provide code sample (both the client and the server side) on how this can be done.
In fact, this question is answered in the App Egnine documentation. See an example on Uploading User Images.
HTML code, inside <form></form>:
<input type="file" name="img"/>
Python code:
class Guestbook(webapp.RequestHandler):
def post(self):
greeting = Greeting()
if users.get_current_user():
greeting.author = users.get_current_user()
greeting.content = self.request.get("content")
avatar = self.request.get("img")
greeting.avatar = db.Blob(avatar)
greeting.put()
self.redirect('/')
Here is a complete, working file. I pulled the original from the Google site and modified it to make it slightly more real world.
A few things to notice:
This code uses the BlobStore API
The purpose of this line in the
ServeHandler class is to "fix" the
key so that it gets rid of any name
mangling that may have occurred in
the browser (I didn't observe any in
Chrome)
blob_key = str(urllib.unquote(blob_key))
The "save_as" clause at the end of this is important. It will make sure that the file name does not get mangled when it is sent to your browser. Get rid of it to observe what happens.
self.send_blob(blobstore.BlobInfo.get(blob_key), save_as=True)
Good Luck!
import os
import urllib
from google.appengine.ext import blobstore
from google.appengine.ext import webapp
from google.appengine.ext.webapp import blobstore_handlers
from google.appengine.ext.webapp import template
from google.appengine.ext.webapp.util import run_wsgi_app
class MainHandler(webapp.RequestHandler):
def get(self):
upload_url = blobstore.create_upload_url('/upload')
self.response.out.write('<html><body>')
self.response.out.write('<form action="%s" method="POST" enctype="multipart/form-data">' % upload_url)
self.response.out.write("""Upload File: <input type="file" name="file"><br> <input type="submit" name="submit" value="Submit"> </form></body></html>""")
for b in blobstore.BlobInfo.all():
self.response.out.write('<li>' + str(b.filename) + '')
class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):
def post(self):
upload_files = self.get_uploads('file')
blob_info = upload_files[0]
self.redirect('/')
class ServeHandler(blobstore_handlers.BlobstoreDownloadHandler):
def get(self, blob_key):
blob_key = str(urllib.unquote(blob_key))
if not blobstore.get(blob_key):
self.error(404)
else:
self.send_blob(blobstore.BlobInfo.get(blob_key), save_as=True)
def main():
application = webapp.WSGIApplication(
[('/', MainHandler),
('/upload', UploadHandler),
('/serve/([^/]+)?', ServeHandler),
], debug=True)
run_wsgi_app(application)
if __name__ == '__main__':
main()
There is a thread in Google Groups about it:
Uploading Files
With a lot of useful code, that discussion helped me very much in uploading files.
Google has released a service for storing large files. Have a look at blobstore API documentation. If your files are > 1MB, you should use it.
I try it today, It works as following:
my sdk version is 1.3.x
html page:
<form enctype="multipart/form-data" action="/upload" method="post" >
<input type="file" name="myfile" />
<input type="submit" />
</form>
Server Code:
file_contents = self.request.POST.get('myfile').file.read()
If your still having a problem, check you are using enctype in the form tag
No:
<form encoding="multipart/form-data" action="/upload">
Yes:
<form enctype="multipart/form-data" action="/upload">
You can not store files as there is not a traditional file system. You can only store them in their own DataStore (in a field defined as a BlobProperty)
There is an example in the previous link:
class MyModel(db.Model):
blob = db.BlobProperty()
obj = MyModel()
obj.blob = db.Blob( file_contents )
Personally I found the tutorial described here useful when using the Java run time with GAE. For some reason, when I tried to upload a file using
<form action="/testservelet" method="get" enctype="multipart/form-data">
<div>
Myfile:<input type="file" name="file" size="50"/>
</div>
<div>
<input type="submit" value="Upload file">
</div>
</form>
I found that my HttpServlet class for some reason wouldn't accept the form with the 'enctype' attribute. Removing it works, however, this means I can't upload any files.
There's no flat file storing in Google App Engine. Everything has to go in to the Datastore which is a bit like a relational database but not quite.
You could store the files as TextProperty or BlobProperty attributes.
There is a 1MB limit on DataStore entries which may or may not be a problem.
I have observed some strange behavior when uploading files on App Engine. When you submit the following form:
<form method="post" action="/upload" enctype="multipart/form-data">
<input type="file" name="img" />
...
</form>
And then you extract the img from the request like this:
img_contents = self.request.get('img')
The img_contents variable is a str() in Google Chrome, but it's unicode in Firefox. And as you now, the db.Blob() constructor takes a string and will throw an error if you pass in a unicode string.
Does anyone know how this can be fixed?
Also, what I find absolutely strange is that when I copy and paste the Guestbook application (with avatars), it works perfectly. I do everything exactly the same way in my code, but it just won't work. I'm very close to pulling my hair out.
There is a way of using flat file system( Atleast in usage perspective)
There is this Google App Engine Virtual FileSystem project. that is implemented with the help of datastore and memcache APIs to emulate an ordinary filesystem. Using this library you can use in you project a similar filesystem access(read and write).
Related
I have to delete database entries conditionally and I couldn't figure out as the form is asking for correct parameters posted in uri. I can delete entries in shell with same code but not in view. Following is the view and form:
#app.route('/cancelannualsub/<int:student_id>', methods=['DELETE'])
def cancel_yearly_rec(student_id):
if not user_authorized():
return redirect('/')
user = get_profile_data(session['auth_token'])
profile_data = user['StudentProfile']
pkg = Package.query.filter_by(student_id=profile_data.id).first_or_404()
if request.method=='POST':
try:
pkg = Package()
dbase.session.delete(pkg)
flash('Package deleted successfully.')
dbase.session.commit()
except:
pass
return redirect('plans')
return render_template('profile/cancel/cancel.html')
Form:
<form action="{{ url_for('cancel_yearly_rec', student_id=***can't render value here***) }}" method='post'>
<input type='hidden' name='_method' value='DELETE'
<input class='btn' type="submit" value="Cancel" />
</form>
I am trying different things from stackoverflow examples. Please assist if I am doing something wrong or if there is a better way to do it.
I wasn't using proper formatting to render model objects inside try block.
It supposed to be something like:
mymodel = Model.query.filter_by(variable=some_field_data).first_or_404()
dbase.session.delete(mymodel)
dbase.session.commit()
For readers don't get confused with "dbase" because I made this import like:
from app import db as dbase
You can import it simply by:
from app import db
or add "as anything".
Then you reference anything in rest of your file where you've made import.
I have this view:
def index(request):
file = open("SK ✌😜✌.txt", encoding="UTF-8")
data = file.read()
file.close()
lines = data.split("\n")
...More code...
In this view i open a file from the very first moment the app starts and i do some work on the file, is a story, and when i start the server and go to http://127.0.0.1:8000/(Name Of The App), i see all the work that i have done on that file.
What i want to do is to do that same work, starting with the reading of the file, BUT i want to do that with the file that the user uploads in that moment. I have this that i took from bootstrap:
<div class="form-group">
<label for="exampleInputFile">File input</label>
<input type="file" id="exampleInputFile">
</div>
I guess i have to use in some way the id of the input but i`m not really sure how to pass this file that the user uploads in the ui to the method that i have in my views.py
Any help will be really appreciated
You need to have a name attribute in your <input> template code.
<input type="file" id="exampleInputFile" name="some_file">
Then to access the file in your view, you need to use request.FILES attribute.
As per the Django docs on HttpRequest.FILES attribute:
A dictionary-like object containing all uploaded files. Each key in
FILES is the name from the <input type="file" name="" />. Each
value in FILES is an UploadedFile.
Your code should be something like:
def index(request):
if request.method=="POST":
uploaded_file = request.FILES['some_file'] # get the uploaded file
# do something with the file
Note: request.FILES will only contain data if the request method was POST and the <form> that posted to the request had enctype="multipart/form-data. Otherwise, FILES will be a blank dictionary-like object.
EDIT: Added the solution to my code, as suggested by Martijn Pieters.
I'm writing a web application that should have an image upload feature. Actually it is uploading directly to imgur.com through their api. So far I can upload an image to imgur through the terminal by running my python script. But I want the user to be able to select an image through an html form. All I actually need (I think) is the path for the file, then I have a script that converts the image to base64. As I write this I realize that the script might only work when it's run locally, and not from a browser. I have been googling for two days. I get a lot of results about cgi.FieldStorage() but can't seem to get that to work as I get a KeyError.
This is the file input part of my form:
<div class="container">
<form role="form" class="form-horizontal form-inline" method="post" enctype="multipart/form-data">
<div class="col-md-12">
<div class="form-group">
<label for="image" class="control-label">Product image</label>
<input type="file" id="image" name="imageurl" value=""/>
</div>
</div>
And then I need to be able to handle the input in my python script:
class MainPage(BlogHandler):
def get(self):
self.render("front.html")
def post(self):
image = self.request.POST.get("imageurl")
logging.info(getUrl(image))
This is the code for sending the image to the imgur api:
def getUrl(image):
API_URL = "https://api.imgur.com/3/upload.json"
image_read = image.file.read()
b64 = base64.b64encode(image_read)
data = {
'image': b64,
'type': base64,
'title': 'testupload'
}
response = requests.post(API_URL, data, headers={'Authorization': 'Client-ID my-cient-id'})
url = response.json()['data']['link']
return url
I developing in Google App Engine and using Jinja2 as the templating engine.
I'm a beginner programmer so I hope to get some pointers on my problem. I feel like I'm stuck on searching for the answer. I've read that the browser does not know anything about the file system of the computer for security reasons, but websites exist where you can choose a file from your computer to upload, so I figure it must be possible to achieve. :)
EDIT: Added the solution to my code, as suggested by Martijn Pieters.
Uploading an image requires that you change the form encoding to multipart/form-data:
<form encoding="multipart/form-data" role="form" class="form-horizontal form-inline" method="post">
See application/x-www-form-urlencoded or multipart/form-data?
Because this is a POST request, you'll find the fields in request.POST:
def post(self):
imageurl = self.request.POST.get("imageurl")
logging.info(imageurl)
although request.get() will search both query parameters and POST form data.
A form upload is returned as a cgi.FieldStorage() object; this has a file attribute, which gives you a file-like interface. You could just read the data into memory:
image = self.request.POST.get("imageurl")
image_read = image.file.read()
b64 = base64.b64encode(image_read)
Here I am trying to upload a file asynchronously to the blobstore. Following is what I've done so far:
html file
<form id="my_form" enctype="multipart/form-data" method="POST"
action="/partner">
<input type="file" id="my_file" name="my_file"/>
</form>
js file
my.Project.prototype.onFileUpload = function(e) {
var uploadForm = /** #type {HTMLFormElement} */ (
goog.dom.getElement('my_form'));
var iframeIo = new goog.net.IframeIo();
goog.events.listen(iframeIo, goog.net.EventType.COMPLETE, function() { alert('request complete'); });
iframeIo.sendFromForm(uploadForm);
python code
class MyHandler(blobstore_handlers.BlobstoreUploadHandler):
def post(self):
logging.info(self.request) // I can see my file in this line's output
upload_files = self.get_uploads('my_file')
logging.info(upload_files) //upload_files come out to be an empty array
blob_info = upload_files[0]
self.redirect('/partner/serve/%s' % blob_info.key())
Any pointers on how to get the file to be uploaded fron the Request object.
The python code provided by google tutorial on blobstore can be found here.
Now I am stuck. I believe if I can get the file in python code I'll be able to upload it.
Any pointers will be very helpful.
Thanks,
Mohit
This isn't really a question about iframeio, but simply about uploading in AppEngine. What you're missing is that you're supposed to create a URL to upload to first, in your GET method, and use that as the action parameter for the form. See the sample application in the AppEngine docs.
So in your case, you'd do upload_url = blobstore.create_upload_url('/partner'), and in your template, <form action="{{ upload_url }}" method="POST" enctype="multipart/form-data">, etc.
As a beginner in Python and App Engine I once again have to ask for your assistance. For some time I've been working with the book "Code in the Cloud" to learn the very basics of using App Engine. The thing is I have not been very successful so far. While most of the issues I have had stemmed from UTF-8 encoding/decoding, this time I have problems with making queries to Datastore.
To learn the basics I recreated the code for a simple chat service available in chapter IV of the aforesaid book. The key elements are:
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
import datetime
from google.appengine.ext import db
#START: ChatMessage
class ChatMessage(db.Model):
user = db.StringProperty(required=True)
timestamp = db.DateTimeProperty(auto_now_add=True)
message = db.TextProperty(required=True)
def __str__(self):
return "%s (%s): %s" % (self.user, self.timestamp, self.message)
#END: ChatMessage
Above, I defined the datamodel for a message
class ChatRoomPage(webapp.RequestHandler):
def get(self):
self.response.headers["Content-Type"] = "text/html"
self.response.out.write("""
<html>
<head>
<title>AppEngine Chat Room</title>
</head>
<body>
<h1>Welcome to AppEngine Chat Room</h1>
<p>(Current time is %s)</p>
""" % (datetime.datetime.now()))
messages = db.GqlQuery("SELECT * From ChatMessage ORDER BY time")
for msg in messages:
self.response.out.write("<p>%s</p>" % msg)
self.response.out.write("""
<form action="/talk" method="post">
<div><b>Name:</b>
<textarea name="name" rows="1" cols="20"></textarea></div>
<p><b>Message</b></p>
<div><textarea name="message" rows="5" cols="60"></textarea></div>
<div><input type="submit" value="Send ChatMessage"/></div>
</form>
</body>
</html>
""")
# END: MainPage
In the block above I create UI and performe a GQL query for data I posted.
Lastly:
class ChatRoomPoster(webapp.RequestHandler):
def post(self):
chatter = self.request.get("name")
msgtext = self.request.get("message")
msg = ChatMessage(user=chatter, message=msgtext)
msg.put()
self.redirect('/')
I create the handler to send the collected data into Datastore.
Having consulted the book line by line, as well as Google tutorial, and a number of threads on this website, I still can't figure out, why the code does not work properly. Basically, the chat won't display past messages. My guess is I am doing something wrong with accessing the stored data, as the program does not throw any exception - I am missing an identifier or something like that. Perhaps I am again missing something very obvious.
I would really appreciate your help. Thank you in advance.
Your query is:
messages = db.GqlQuery("SELECT * From ChatMessage ORDER BY time")
but your datastore model doesn't have a time property, it has a timestamp property. Attempting to order by a property that isn't on any entities will always return an empty resultset.
In your for loop over the messages, 'msg' is a datastore object. You need to reference a specific attribute (ie msg.message).
for msg in messages:
self.response.out.write("<p>%s</p>" % msg.message)