up

ethlite-contracts/README.md

@@ -11,9 +11,88 @@ ethlite-contracts  - ready-to-use (blockchain) contract services / function call
 
 
 
-## Usage
+## Usage by Example
+
+### Contract №1 - PunksMeta  (aka CryptoPunksTokenUri)  by 0xTycoon
+
+_The missing tokenURI() for the Punks_
+
+
+Let's try the `PunksMeta` contract
+with  the token id 0, that is, punk no. 0:
+
+``` ruby
+require 'ethlite/contracts'
+
+contract = PunksMeta.new
+
+
+#  function parseAttributes(uint256 _tokenId) returns (string[8])
+#
+#  parseAttributes returns an array of punk attributes. 8 rows in total
+#      The first row is the Type, and next seven rows are the attributes.
+#      The values are fetched form the CryptoPunksData contract and then the
+#      string is parsed.
+#    @param _tokenId the punk id
+ary = contract.parseAttributes( 0 )
+#=> ["Female 2", "Earring", "Blonde Bob", "Green Eye Shadow", "", "", "",
+
+
+#  function getAttributes(uint256 _tokenId) returns (string)
+#
+#  getAttributes calls parseAttributes and returns the result as JSON
+#    @param _tokenId the punk id
+str = contract.getAttributes( 0 )
+data = JSON.parse( str )
+#=> [{"trait_type"=>"Type", "value"=>"Female 2"},
+#    {"trait_type"=>"Accessory", "value"=>"Earring"},
+#    {"trait_type"=>"Accessory", "value"=>"Blonde Bob"},
+#    {"trait_type"=>"Accessory", "value"=>"Green Eye Shadow"}]
+
+
+#  function tokenURI(uint256 _tokenId)  returns (string)
+#
+#  tokenURI gets the metadata about a punk and returns as a JSON
+#      formatted string, according to the ERC721 schema and market
+#      recommendations. It also embeds the SVG data.
+#      The attributes and SVG data are fetched form the CryptoPunksData
+#      contract, which stores all the CryptoPunks metadata on-chain.
+#    @param _tokenId the punk id
+str = contract.tokenURI( 0 )
+if str.start_with?( 'data:application/json;base64,' )
+  str = str.sub( 'data:application/json;base64,', '' )
+  ## get metadata (base64-encoded)
+  data = JSON.parse( Base64.decode64( str ) )
+#=> {"description"=> "CryptoPunks launched as a fixed set of 10,000 items in mid-2017...",
+#    "external_url"=>"https://cryptopunks.app/cryptopunks/details/0",
+#    "image"=> "data:image/svg+xml;base64,...",
+#    "name"=>"CryptoPunk #0",
+#    "attributes"=>
+#      [{"trait_type"=>"Type", "value"=>"Female 2"},
+#       {"trait_type"=>"Accessory", "value"=>"Earring"},
+#       {"trait_type"=>"Accessory", "value"=>"Blonde Bob"},
+#       {"trait_type"=>"Accessory", "value"=>"Green Eye Shadow"}]}
+
+      ## get image (base64-encoded)
+      str_image = data.delete( 'image' )
+      str_image = str_image.sub( 'data:image/svg+xml;base64,', '' )
+      image = Base64.decode64( str_image )
+      ## cut-off inline leading data:image/svg+xml;utf8, too
+      image = image.sub( 'data:image/svg+xml;utf8,', '' )
+
+      write_json( "punksmeta/punk0.json", data )
+      write_text( "punksmeta/punk0.svg", image )
+   else
+     puts "!! ERROR - expected json base64-encoded; got:"
+     pp str
+     exit 1
+   end
+end
+```
+
+Note:  See [`punksmeta/punk0.json`](punksmeta/punk0.json)
+and [`punksmeta/punk0.svg`](punksmeta/punk0.svg) for the saved copies of the data.
 
-To be done
 
 
 

ethlite-contracts/punksmeta/punk0.json

@@ -0,0 +1,23 @@
+{
+  "description": "CryptoPunks launched as a fixed set of 10,000 items in mid-2017 and became one of the inspirations for the ERC-721 standard. They have been featured in places like The New York Times, Christie's of London, Art|Basel Miami, and The PBS NewsHour.",
+  "external_url": "https://cryptopunks.app/cryptopunks/details/0",
+  "name": "CryptoPunk #0",
+  "attributes": [
+    {
+      "trait_type": "Type",
+      "value": "Female 2"
+    },
+    {
+      "trait_type": "Accessory",
+      "value": "Earring"
+    },
+    {
+      "trait_type": "Accessory",
+      "value": "Blonde Bob"
+    },
+    {
+      "trait_type": "Accessory",
+      "value": "Green Eye Shadow"
+    }
+  ]
+}