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atproto
1# How to Extract rkey from AT Protocol CAR Files
2
3The **rkey** (record key) is not stored inside the IPLD record data itself. Instead, it's found in **commit operations** that map collection paths to record CIDs.
4
5## AT Protocol Structure
6
7```
8Repository Structure:
9├── Records (IPLD blocks)
10│ ├── bafyrei123... (actual play record data)
11│ ├── bafyrei456... (actual profile record data)
12│ └── bafyrei789... (actual post record data)
13└── Commits (IPLD blocks)
14 ├── bafycommit1... (operations mapping paths to CIDs)
15 └── bafycommit2... (more operations)
16```
17
18## Example: Record IPLD (without rkey)
19
20```json
21{
22 "$type": "fm.teal.alpha.feed.play",
23 "track_name": "Bohemian Rhapsody",
24 "artist_names": ["Queen"],
25 "duration": 355000,
26 "played_time": "2024-01-15T14:30:00Z"
27}
28```
29
30**❌ No rkey here!** The record contains the data but not its key.
31
32## Example: Commit IPLD (with rkey mappings)
33
34```json
35{
36 "ops": [
37 {
38 "action": "create",
39 "path": "fm.teal.alpha.feed.play/3k2akjdlkjsf", // ← collection/rkey
40 "cid": "bafyrei123..." // ← points to the record above
41 },
42 {
43 "action": "create",
44 "path": "fm.teal.alpha.actor.profile/self",
45 "cid": "bafyrei456..."
46 }
47 ],
48 "prev": "bafyrei...",
49 "rev": "3k2bkl...",
50 "time": "2024-01-15T14:35:00Z"
51}
52```
53
54**✅ rkey is here!** Extract it from the `path` field: `"3k2akjdlkjsf"`
55
56## Extraction Algorithm
57
58```rust
59fn extract_rkeys_from_commits(commits: &[CommitInfo]) -> HashMap<String, String> {
60 let mut cid_to_rkey = HashMap::new();
61
62 for commit in commits {
63 for operation in &commit.operations {
64 // Path format: "collection/rkey"
65 if let Some(rkey) = operation.path.split('/').last() {
66 if let Some(ref record_cid) = operation.record_cid {
67 cid_to_rkey.insert(record_cid.clone(), rkey.to_string());
68 }
69 }
70 }
71 }
72
73 cid_to_rkey
74}
75```
76
77## Complete Example
78
791. **Find commit blocks** in CAR file
802. **Extract operations** from commit IPLD
813. **Parse paths** like `"fm.teal.alpha.feed.play/3k2akjdlkjsf"`
824. **Map CID → rkey**: `bafyrei123... → 3k2akjdlkjsf`
835. **Use rkey** when processing records
84
85## Why This Matters
86
87The rkey is essential for:
88- **AT URI construction**: `at://did:plc:user123/fm.teal.alpha.feed.play/3k2akjdlkjsf`
89- **Record identity**: Uniquely identifies the record within the collection
90- **Data integrity**: Maintains proper AT Protocol addressing
91
92## CLI Usage
93
94```bash
95# Explore CAR file and show rkey extraction
96teal car explore --file archive.car --verbose
97
98# The verbose output will show:
99# 🔑 rkey Extraction Examples:
100# 1. bafyrei123... → rkey: 3k2akjdlkjsf
101# 2. bafyrei456... → rkey: self
102```
103
104**Note**: Some CAR files may not contain commit operations with rkey mappings, especially if they're partial exports or contain only raw records without repository structure.