Simple README

README.md

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+# Imgproxy
+
+Tiny, fast and secure server for processing remote images.
+
+### How to generate url path
+
+Full README is on the way. Here is a short sample which shows how to generate url
+path for imgproxy.
+
+```ruby
+require 'openssl'
+require 'base64'
+
+# Key and salt. Since they're hex-encoded, we should decode it.
+key = ['943b421c9eb07c830af81030552c86009268de4e532ba2ee2eab8247c6da0881'].pack("H*")
+salt = ['520f986b998545b4785e0defbc4f3c1203f22de2374a3d53cb7a7fe9fea309c5'].pack("H*")
+
+# This is remote url with requested image
+url = "http://img.example.com/pretty/image.jpg"
+
+# Url should be encoded with base64 and could be splitted
+encodedUrl = Base64.urlsafe_encode64(url).tr("=", "").scan(/.{1,16}/).join("/")
+
+# Allowed values for resize are: fill, fit, crop and resize
+resize = 'fill'
+width = 300
+height = 300
+# Allowed values for gravity are: no (north), so (south), ea (east), we (west)
+# ce (center) and sm (smart). "sm" works correctly only with resize == crop.
+gravity = 'no'
+# Should we enlarge small images? 1 for yes, and 0 for no.
+enlarge = 1
+# Allowed extensions are png and jpg/jpeg.
+extension = 'png'
+
+path = "/#{resize}/#{width}/#{height}/#{gravity}/#{enlarge}/#{encodedUrl}.#{extension}"
+
+# Now we need to sign path with HMAC (SHA256)
+digest = OpenSSL::Digest.new('sha256')
+hmac = Base64.urlsafe_encode64(OpenSSL::HMAC.digest(digest, key, "#{salt}#{path}")).tr('=', '')
+
+signed_path = "/#{hmac}#{path}"
+```