Blob Inspector

The Corda blob inspector tool gives you a human-readable view of content stored in a custom binary serialization format. The blob inspector shows you the output of binary blob files (or URL end-points) in YAML or JSON using JacksonSupport (see JSON for more on Jackson serialization).

The tool is distributed as a .jar. file - corda-tools-blob-inspector-4.12.jar. To run it, pass in the file or URL as the first parameter:

java -jar corda-tools-blob-inspector-4.12.jar <file or URL>

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

The serialization framework can synthesize any classes found in the blob that are not on the classpath. That means you don’t need to include the JARs containing the class definitions when inspecting your custom data structures.

Supported formats

The inspector can read input data in three formats: raw binary, hex encoded text, and Base64 encoded text. The tool will try each format until one works.

You may find it useful to know that Corda’s format always starts with the word “corda” in binary. Try hex decoding 636f726461 using the online hex decoder tool to see for yourself.

Output data can be in either a slightly extended form of YAML or JSON. YAML (Yet another Markup Language) is easier for humans to read, and is the default. JSON can be parsed by any JSON library in any language.

Example

Here’s what a node-info file from the node’s data directory may look like:

• 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==

• 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 serialized SignedNodeInfo object, which has a raw property of type SerializedBytes<NodeInfo>. This property is materialized into NodeInfo and is output under the deserialized field.

Classpath

If you run the blob inspector without any JAR files on the classpath, then it will deserialize objects using the class carpenter, (see Object serialization). This happens because the types are not available, so the serialization framework has to synthesize them.

Command-line options

You can start the blob inspector with the following command line options:

blob-inspector [-hvV] [--full-parties] [--schema] [--format=type]
               [--input-format=type] [--logging-level=<loggingLevel>] SOURCE
               [COMMAND]

• --format=type: Output format. Possible values: [YAML, JSON]. Default: YAML.
• --input-format=type: Input format. If the file can’t be decoded with the given value it’s auto-detected, so you should never normally need to specify this. Possible values [BINARY, HEX, BASE64]. Default: BINARY.
• --full-parties: Display the owningKey and certPath properties of Party and PartyAndReference objects respectively.
• --schema: Print the blob’s schema first.
• --verbose, --log-to-console, -v: If set, prints logging to the console as well as to a file.
• --logging-level=<loggingLevel>: Enable logging at this level and higher. Possible values: ERROR, WARN, INFO, DEBUG, TRACE. Default: INFO.
• --help, -h: Show this help message and exit.
• --version, -V: Print version information and exit.

Sub-commands

install-shell-extensions: Install blob-inspector alias and auto-completion for bash and zsh. See Shell extensions for CLI Applications.