feat: proof add --dry-run --json to view a delegation (#40)

adds `--dry-run` so we can view info about a proof without adding it.
Useful for debugging, and as `proof add` changes local state, it's
always nice to have a dry run option.

```bash
$ w3 proof add ~/Downloads/did-key-z6MkvqaczH.ucan --dry-run
bafyreidzajq4jptufyiuhq7t7xtf2uiglgjb27rxf5acqtqpirmx3jvy54
  issuer: did:key:z4MXj1wBzi9jUstyPzbX4dasDsxqd7cRCPgpzRQJa9tkywBu3rouGzwWJt1rnvixptH54i4TA552Sq52asiZTBBaRJ2gjJagE9niiZawBBoKpBdZVCTrFPp2poAkyBezvTegXVWziimVftBUCymosNroW3TwApSYPXdczeU5WjEJFn9isdZuZcs99xYtV3f7Uri7tp3ymrXnioshMNgP1FqU5VgniuwA9oV1BFzjjPra7GLXxMoD6jv8j68v8McyGu4EyQ5AFhdLBVLiQg3TU14ew8hhrVaMnF5Csvf1KYpZ1ahBDo6KZ4ZYMDE4M4fPVfuCHZju4UN7aq996VJ3RpfBfhPrQLXwopZ3JcuBjzboMmzjAJNs2
  with: did:key:z6MksH388fHkXCsqDuzyVaHGHaKtwxaFESoL7vV6xqZRLz8R
  can: *
```

adds missing `--json` flag handling and updates deps so we can make use
of the new `toJSON` method on `Delegation`

```bash
$ w3 proof add ~/Downloads/did-key-z6MkvqaczH.ucan --dry-run --json
{"iss":"did:key:z4MXj1wBzi9jUstyPzbX4dasDsxqd7cRCPgpzRQJa9tkywBu3rouGzwWJt1rnvixptH54i4TA552Sq52asiZTBBaRJ2gjJagE9niiZawBBoKpBdZVCTrFPp2poAkyBezvTegXVWziimVftBUCymosNroW3TwApSYPXdczeU5WjEJFn9isdZuZcs99xYtV3f7Uri7tp3ymrXnioshMNgP1FqU5VgniuwA9oV1BFzjjPra7GLXxMoD6jv8j68v8McyGu4EyQ5AFhdLBVLiQg3TU14ew8hhrVaMnF5Csvf1KYpZ1ahBDo6KZ4ZYMDE4M4fPVfuCHZju4UN7aq996VJ3RpfBfhPrQLXwopZ3JcuBjzboMmzjAJNs2","aud":"did:key:z6MkvqaczHouddZ91gWNsuy2QFm419WFodXbVjBJykvzw1eK","v":"0.9.1","s":{"/":{"bytes":"haTABoACShdnoTAfihQ2lag5Caf4+P7TkLK/EFtfpX6EUEvI1Dp9MdoRIYDylpm8ovKXXS5FkziQHRJvGpBcGN25be9CegywiudM/bNB5rBcmgYGSSkGvoQZLTgckiezGMdKI1S6/SbYvTK4VShIsrxWXKhMLgH2JMHAXTo123mLdV3WIVzWbu0VJBm1pY6lRxDJcQbzrVL/yk6WLlmlDgCqSweqAMV+GDfWE+xaC3Mot/m+LIWAemNB/nMnyOwuaihfJ5C17nxdRDY0Kmkweq4+W4CiG7yK333wLM2vjJoJOmaIvAPJI8i5x8h8JZXwPJL/EEPzdPbfwujMY7FyUTZADHGnWQ"}},"exp":null,"att":[{"can":"*","with":"did:key:z6MksH388fHkXCsqDuzyVaHGHaKtwxaFESoL7vV6xqZRLz8R"}],"fct":[{"space":{"isRegistered":true,"name":"Shared with cli"}}],"prf":[{"iss":"did:key:z6MksH388fHkXCsqDuzyVaHGHaKtwxaFESoL7vV6xqZRLz8R","aud":"did:key:z4MXj1wBzi9jUstyPzbX4dasDsxqd7cRCPgpzRQJa9tkywBu3rouGzwWJt1rnvixptH54i4TA552Sq52asiZTBBaRJ2gjJagE9niiZawBBoKpBdZVCTrFPp2poAkyBezvTegXVWziimVftBUCymosNroW3TwApSYPXdczeU5WjEJFn9isdZuZcs99xYtV3f7Uri7tp3ymrXnioshMNgP1FqU5VgniuwA9oV1BFzjjPra7GLXxMoD6jv8j68v8McyGu4EyQ5AFhdLBVLiQg3TU14ew8hhrVaMnF5Csvf1KYpZ1ahBDo6KZ4ZYMDE4M4fPVfuCHZju4UN7aq996VJ3RpfBfhPrQLXwopZ3JcuBjzboMmzjAJNs2","v":"0.9.1","s":{"/":{"bytes":"7aEDQA53nQmLquoq3Xfu1o+L88SLMMGivLCNcLNvUO+B2opkHyIJs83RVFRMEL1mjrKJzVAiGzHmDd6AJTwHX4CTqg0"}},"exp":null,"att":[{"can":"*","with":"did:key:z6MksH388fHkXCsqDuzyVaHGHaKtwxaFESoL7vV6xqZRLz8R"}],"prf":[],"/":"bafyreihfyvjcrenryrexbyeddgntfbn2mjvx57hiiav2jbceqh2v2taame"}],"/":"bafyreidzajq4jptufyiuhq7t7xtf2uiglgjb27rxf5acqtqpirmx3jvy54"}
```

Convert any errors to a simple error message instead of dumping stack

```bash
$ w3 proof add ~/Downloads/w3cli.ucan 
Error: Delegation audience does not match required DID.
```

License: MIT
Signed-off-by: Oli Evans <oli@protocol.ai>

bin.js

@@ -100,6 +100,7 @@ cli.command('delegation ls')
 cli.command('proof add <proof>')
   .describe('Add a proof delegated to this agent.')
   .option('--json', 'Format as newline delimted JSON')
+  .option('--dry-run', 'Decode and view the proof but do not add it')
   .action(addProof)
 
 cli.command('proof ls')

index.js

@@ -279,16 +279,31 @@ export async function listDelegations (opts) {
 
 /**
  * @param {string} proofPath
+ * @param {object} opts
+ * @param {boolean} [opts.json]
+ * @param {boolean} [opts.dry-run]
  */
-export async function addProof (proofPath) {
+export async function addProof (proofPath, opts) {
   const client = await getClient()
-  const proof = await readProof(proofPath)
-  await client.addProof(proof)
-  console.log(proof.cid.toString())
-  console.log(`  issuer: ${proof.issuer.did()}`)
-  for (const capability of proof.capabilities) {
-    console.log(`  with: ${capability.with}`)
-    console.log(`  can: ${capability.can}`)
+  let proof
+  try {
+    proof = await readProof(proofPath)
+    if (!opts['dry-run']) {
+      await client.addProof(proof)
+    }
+  } catch (err) {
+    console.log(`Error: ${err.message}`)
+    process.exit(1)
+  }
+  if (opts.json) {
+    console.log(JSON.stringify(proof.toJSON()))
+  } else {
+    console.log(proof.cid.toString())
+    console.log(`  issuer: ${proof.issuer.did()}`)
+    for (const capability of proof.capabilities) {
+      console.log(`  with: ${capability.with}`)
+      console.log(`  can: ${capability.can}`)
+    }
   }
 }