adding the is_json tool and associated readme.md details

plugins/jsontools/README.md

@@ -5,10 +5,11 @@ Handy command line tools for dealing with json data.
 ## Tools
 
 - **pp_json** - pretty prints json
+- **is_json** - returns true if valid json; false otherwise
 
-## Usage
+## Examples
 
-##### pp_json - examples
+##### pp_json
 
 ```sh
 # curl json data and pretty print the results
@@ -20,3 +21,15 @@ less data.json | pp_json
 # json data directly from the command line
 echo '{"b":2, "a":1}' | pp_json
 ```
+
+##### is_json
+```sh
+# curl json data and pretty print the results
+curl https://coderwall.com/bobwilliams.json | is_json
+
+# pretty print the contents of an existing json file
+less data.json | is_json
+
+# json data directly from the command line
+echo '{"b":2, "a":1}' | is_json
+```

plugins/jsontools/jsontools.plugin.zsh

@@ -7,10 +7,21 @@ fi
 
 if [[ $(whence node) != "" && ( "x$JSONTOOLS_METHOD" = "x"  || "x$JSONTOOLS_METHOD" = "xnode" ) ]]; then
 	alias pp_json='xargs -0 node -e "console.log(JSON.stringify(JSON.parse(process.argv[1]), null, 4));"'
+	alias is_json='xargs -0 node -e "try {json = JSON.parse(process.argv[1]);} catch (e) { console.log(false); json = null; } if(json) { console.log(true); }"'
 elif [[ $(whence python) != "" && ( "x$JSONTOOLS_METHOD" = "x" || "x$JSONTOOLS_METHOD" = "xpython" ) ]]; then
 	alias pp_json='python -mjson.tool'
+	alias is_json='python -c "
+import json, sys;
+try: 
+	json.loads(sys.stdin.read())
+except ValueError, e: 
+	print False
+else:
+	print True
+sys.exit(0)"'
 elif [[ $(whence ruby) != "" && ( "x$JSONTOOLS_METHOD" = "x" || "x$JSONTOOLS_METHOD" = "xruby" ) ]]; then
 	alias pp_json='ruby -e "require \"json\"; require \"yaml\"; puts JSON.parse(STDIN.read).to_yaml"'
+	alias is_json='ruby -e "require \"json\"; begin; JSON.parse(STDIN.read); puts true; rescue Exception => e; puts false; end"'
 fi
 
 unset JSONTOOLS_METHOD