I wrote a simple Sinatra app that generate an image using rmagick from some user inputs. The image is saved in the ./public directory with a unique file name. The unique file name is used in the HTML generated by Sinatra so that each user gets the correct image. Once a day a script deletes files older than one hour. This is clearly a terrible hack but I have no web experience!
Is there any way to serve the rmagick image in sinatra without first saving it to disk?
Use the Image#to_blob method to turn the in-memory image into a string:
get '/' do
content_type 'image/png'
img = Magick::Image.read('logo:')[0]
img.format = 'png'
img.to_blob
end
Related
I having been trying to write a script that scrapes a page for images the way it has been outlined in
"Save all image files from a website".
I tested that method with another page and it worked fine, but when inserting my link to scrape data:image URIs, which look like:
data:image/jpg;base64,/9j/4FEJFOIEJNFOEJOIAD//gAQTGFGRGREGg2LjEwMAD/2wBDAAgEBAQEREGREWGRWEGUFBQYGBgYGBgYGB...
I get an error beginning with initialize': File name too long and ending in (Errno::ENAMETOOLONG).
Has anyone found a way to deal with situations like this?
data:image URLs actually contain the image inline as base 64. All you need to do is grab that data and decode it:
require 'base64'
File.open(File.basename(uri),'wb'){ |f| f.write(Base64.decode64(url[/base64,(.*)/, 1])) }
I'm using carrier wave, rails and amazon s3. Every time I save an image, the image shows up in s3 and I can see it in the management console with the name like this:
https://s3.amazonaws.com/bucket-name/
uploads/images/10/888fdcfdd6f0eeea_1351389576.png
But in the model, the name is this:
https://bucket-name.s3.amazonaws.com/
uploads/images/10/b3ca26c2baa3b857_1351389576.png
First off, why is the random name different? I am generating it in the uploader like so:
def filename
if original_filename
"#{SecureRandom::hex(8)}_#{Time.now.to_i}#{File.extname(original_filename).downcase}"
end
end
I know it is not generating a random string every call because the wrong url in the model is consistent and saved. Somewhere in the process a new one must be getting generated to save in the model after the image name has been saved and sent to amazon s3. Strange.
Also, can I have the url match the one in terms of s3/bucket instead of bucket.s3 without using a regex? Is there an option in carrierwave or something for that?
CarrierWave by default doesn't store the URL. Instead, it generates it every time you need it.
So, every time filename is called it will return a different value, because of Time.now.to_i.
Use created_at column instead, or add a new column for storing the random id or the full filename.
I solved it by saving the filename if it was still the original filename. In the uploader, put:
def filename
if original_filename && original_filename == #filename
#filename = "#{any_string}#{File.extname(original_filename).downcase}"
else
#filename
end
end
The issue of the sumbdomain versus the path is not actually an issue. It works with the subdomain. I.e. https://s3.amazonaws.com/bucket-name/ and https://bucket-name.s3.amazonaws.com/ both work fine.
I have a rails 3 app where I am using the 'face' gem to reference the Face.com API. The api method takes a parameter of the form:
:file => File.new(path_to_file, 'rb')
which works.
I am trying to change the flow of the app so that the file can be uploaded via a form, do some work with RMagick and then make the API call, all without saving the file to disk.
I can generate the RMagick 'Image' with
image = Magick::Image.from_blob(upload_image_field.read)
I can then manipulate the file with RMagick and even save the results into the database with:
self.data = image.to_blob #normally 'upload_image_field.read' if not using RMagick
My problem is that I can't change the image file (or the blob) into something that the API will recognize (without saving it to disk and then referencing the file on disk).
For example using this in the API method fails:
:file => image.to_blob
How do I convert he blob into the same format as
File.new(path_to_file, 'rb')
Thanks
OK, I could be wrong on this one... but I wanted to dig this up. Unfortunately, you just have to live with saving it as a file. The reason is because the API makes an HTTP POST. Unfortunately, this needs to be a file.
References from: [https://github.com/rociiu/face/tree/master/lib/face]:
recognition.rb:
def faces_detect(opts={})
opts.assert_valid_keys(:urls, :file, :detector, :attributes, :callback, :callback_url)
make_request(:faces_detect, opts)
end
utils.rb:
def make_request(api_method, opts={})
....
response = JSON.parse( RestClient.post(API_METHODS[ api_method ], opts.merge(api_crendential)).body )
....
end
So, why is it a problem to save to a file then?
Does anyone have any insights into using CarrierWave with an ActiveResource model (in Rails 3)? I've got an ActiveResource model with field for the filename, and I want to save the file to the remote filesystem.
I've tried a few things without much success (or conviction that I was doing anything remotely correctly), so I'd appreciate suggestions from anyone who's successfully implemented CarrierWave without using the ORM modules already included in the gem.
I'm probably late for this as the original author has moved on, but this question comes up at the top when someone searches for "carrierwave activeresource", so I thought it was still worth answering.
For the sake of discussion, let's assume we have a model named Artist with a picture named artist_picture mounted as a CarrierWave uploader. With ActiveRecord, you would assign this picture to a File:
artist.artist_picture=File.open('ravello.jpg')
And when you save artist:
artist.save!
the picture will be saved, also.
Now, let's say I create a resource based on this:
class Artist < ActiveResource::Base
end
If I subsequently read in an artist:
artist = Artist.find(1)
and look at it, I'll find this in there:
#<Artist:0x39432039 #attributes={"id"=>1, "name"=>"Ravello", "artist_picture"=>#<ArtistPicture:0x282347249243 #attributes={"url"=>"/uploads/artists/artist_picture/1/ravello.jpg"}, #prefix_options={}, #persisted=false>, #prefix_options={}, #persisted=false>
Interestingly, artist_picture is itself a model and we could declare it and play around with it if we wanted. As it is, you can use the url to grab the picture if you want. But let's talk instead about uploading another picture.
We can add this little bit of code to the Artist model on the server side:
def artist_picture_as_base64=(picsource)
tmpfile = Tempfile.new(['artist','.jpg'], Rails.root.join('tmp'), :encoding => 'BINARY')
begin
tmpfile.write(Base64.decode64(picsource.force_encoding("BINARY")))
file = CarrierWave::SanitizedFile.new(tmpfile)
file.content_type = 'image/jpg'
self.artist_picture = file
ensure
tmpfile.close!
end
end
I'm just showing a simple example - you should probably pass the original filename, also. Anyway, on the resource side:
class Artist < ActiveResource::Base
def artist_picture=(filename)
self.artist_picture_as_base64=Base64.encode64(File.read(filename))
end
end
At this point, on the resource side you need only set "artist_picture" to a filename and it will be encoded and sent when the resource is saved. On the server side, the file will be decoded and saved. Presumably you could skip base64 encoding by just forcing the string to binary encoding, but it craps when I do that and I don't have the patience to track it down. Encoding as base64 works.
I am trying to do something quite simple using Sinatra and RMagick.
Take a image, through a simple form
file upload
Use RMagick to resize it
Then store it in a database for
persistence (irrelevant)
But after going through the RDocs and endless head banging testing
I can't seem to get the form image to a RMagick object cleanly.
This is the horrible thing that is currently working for me:
def image_resize(img_data)
filecount = rand
writer = File.new("/tmp/#{filecount}.jpg", "w")
writer.puts(img_data)
writer.close
resized_image = Magick::ImageList.new("/tmp/#{filecount}.jpg").first
resized_image.crop_resized!(100,100, Magick::NorthGravity)
resized.format = 'jpeg'
resized_image.to_blob
end
#call the method with my form image data
image_resize(params[:image][:tempfile].read)
So how do I do the obvious right thing and just stick my form image data straight into a RMagick object without having to write and read the disk.
I have tried various ways of reading in Magick::Image and ImageLists but have only got an abundance of errors barfed at me.
Thanks for any kind of direction
-1.2.
You need to get the path from the tempfile and pass that to Magick::Image’s read.
Here’s an example:
post "/upload-photo" do
image = Magick::Image.read(params[:image][:tempfile].path)[0]
image.crop_resized! 100, 100, Magick::CenterGravity
store_image_data image.to_blob
redirect "/done"
end
Or you can read straight from the ActionDispatch::Http::UploadedFile like so:
image = Magick::Image.from_blob(params[:image].read)