Blob Inspector

There are many benefits to having a custom binary serialisation format (see Object serialization for details) but one disadvantage is the inability to view the contents in a human-friendly manner. The blob inspector tool alleviates this issue by allowing the contents of a binary blob file (or URL end-point) to be output in either YAML or JSON. It uses JacksonSupport to do this (see JSON).

The latest version of the tool can be downloaded from here.

To run simply pass in the file or URL as the first parameter:

java -jar blob-inspector.jar <file or URL>

Use the --help flag for a full list of command line options.

When inspecting your custom data structures, there’s no need to include the jars containing the class definitions for them in the classpath. The blob inspector (or rather the serialization framework) is able to synthesis any classes found in the blob that aren’t on the classpath.

SerializedBytes

One thing to note is that the binary blob may contain embedded SerializedBytes objects. Rather than printing these out as a Base64 string, the blob inspector will first materialise them into Java objects and then output those. You will see this when dealing with classes such as SignedData or other structures that attach a signature, such as the nodeInfo-* files or the network-parameters file in the node’s directory. For example, the output of a node-info file may look like:

-\-format=YAML

net.corda.nodeapi.internal.SignedNodeInfo
---
raw:
  class: "net.corda.core.node.NodeInfo"
  deserialized:
    addresses:
    - "localhost:10005"
    legalIdentitiesAndCerts:
    - "O=BankOfCorda, L=London, C=GB"
    platformVersion: 4
    serial: 1527851068715
signatures:
- !!binary |-
  VFRy4frbgRDbCpK1Vo88PyUoj01vbRnMR3ROR2abTFk7yJ14901aeScX/CiEP+CDGiMRsdw01cXt\nhKSobAY7Dw==

-\-format=JSON

net.corda.nodeapi.internal.SignedNodeInfo
{
  "raw" : {
    "class" : "net.corda.core.node.NodeInfo",
    "deserialized" : {
      "addresses" : [ "localhost:10005" ],
      "legalIdentitiesAndCerts" : [ "O=BankOfCorda, L=London, C=GB" ],
      "platformVersion" : 4,
      "serial" : 1527851068715
    }
  },
  "signatures" : [ "VFRy4frbgRDbCpK1Vo88PyUoj01vbRnMR3ROR2abTFk7yJ14901aeScX/CiEP+CDGiMRsdw01cXthKSobAY7Dw==" ]
}

Notice the file is actually a serialised SignedNodeInfo object, which has a raw property of type SerializedBytes<NodeInfo>. This property is materialised into a NodeInfo and is output under the deserialized field.