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annotate src/SourceGraph.ts @ 137:a8939c717015
still trying to get build right, but there are other update bugs too
| author | drewp@bigasterisk.com |
|---|---|
| date | Sat, 06 May 2023 15:34:40 -0700 |
| parents | 73a70d00fb74 |
| children | cf642d395be4 |
| rev | line source |
|---|---|
| 128 | 1 import { JsonLdParser } from "jsonld-streaming-parser"; |
| 2 import { Parser, Store } from "n3"; | |
| 3 import { SubEvent } from "sub-events"; | |
| 4 import { Patch } from "./Patch"; | |
| 5 | |
| 6 // Possibly-changing graph for one source. Maintains its own dataset. | |
| 7 // Read-only. | |
| 8 // | |
| 9 // Rename to RemoteGraph? RemoteStore? SyncedStore? PatchableGraph? | |
| 10 export class SourceGraph { | |
| 11 store: Store; // const; do not rebuild | |
| 12 isCurrent: boolean = false; | |
| 13 sourceGraphChanged: SubEvent<Patch> = new SubEvent(); | |
| 14 constructor(public url: string /* immutable */) { | |
| 15 this.store = new Store(); | |
| 16 } | |
| 17 | |
| 18 dispose() {} | |
| 19 | |
| 20 // Call this first, after you've subscribed to `sourceGraphChanged`. This call may | |
| 21 // synchronously fire change events. | |
| 22 // | |
| 23 async reloadRdf() { | |
| 24 const resp = await fetch(this.url); | |
| 25 const ctype = resp.headers.get("content-type"); | |
| 26 if (ctype?.startsWith("text/event-stream")) { | |
| 27 await this.reloadEventStream(); | |
| 28 } else { | |
| 29 await this.reloadSimpleFile(resp); | |
| 30 } | |
| 31 } | |
| 32 | |
| 33 private async reloadEventStream(): Promise<void> { | |
| 34 return new Promise((res, rej) => { | |
| 35 // todo deal with reconnects | |
| 36 const ev = new EventSource(this.url); | |
| 37 let firstPatch = true; | |
| 38 // clear store here? | |
| 39 | |
| 40 // maybe the event messages should be 'add' and 'del', | |
| 41 // for less parsing and clearer order of ops. | |
| 42 ev.addEventListener("patch", async (ev) => { | |
|
137
a8939c717015
still trying to get build right, but there are other update bugs too
drewp@bigasterisk.com
parents:
130
diff
changeset
|
43 // this is reentrant- ok? |
|
a8939c717015
still trying to get build right, but there are other update bugs too
drewp@bigasterisk.com
parents:
130
diff
changeset
|
44 |
|
130
73a70d00fb74
dep upgrades; working on build+release setup
drewp@bigasterisk.com
parents:
128
diff
changeset
|
45 const patchMsg = JSON.parse((ev as any).data); |
| 128 | 46 |
| 47 const p = new Patch(); | |
| 48 | |
| 49 const parser = new JsonLdParser(); | |
| 50 parser.write(JSON.stringify(patchMsg.patch.adds)); | |
| 51 parser.end(); | |
| 52 | |
| 53 await p.streamImport(parser); | |
| 54 this.isCurrent = true; | |
| 55 | |
| 56 p.applyToStore(this.store); | |
| 57 console.log("patchlife0: eventsream store changed"); | |
|
137
a8939c717015
still trying to get build right, but there are other update bugs too
drewp@bigasterisk.com
parents:
130
diff
changeset
|
58 // firing before there are listeners |
| 128 | 59 this.sourceGraphChanged.emit(p); |
| 60 if (firstPatch) { | |
| 61 firstPatch = false; | |
| 62 res(); | |
| 63 } | |
| 64 }); | |
| 65 }); | |
| 66 } | |
| 67 | |
| 68 private async reloadSimpleFile(resp: Response) { | |
| 69 const bodyText = await resp.text(); | |
| 70 const parser = new Parser({ format: "application/trig" }); | |
| 71 await new Promise<void>((res, rej) => { | |
| 72 parser.parse(bodyText, (error, quad, prefixes) => { | |
| 73 if (error) { | |
| 74 console.log("parse ~ error:", error); | |
| 75 rej(error); | |
| 76 return; | |
| 77 } | |
| 78 if (quad) { | |
| 79 this.store.addQuad(quad); // prob want to do this as one or a small number of patches | |
| 80 } else { | |
| 81 res(); | |
| 82 } | |
| 83 }); | |
| 84 }); | |
| 85 this.isCurrent = true; | |
| 86 // this may have to fire per addQuad call for correctness, or else we batch the adds where no readers can see them in advance. | |
| 87 console.log("patchlife0: simple file store changed"); | |
| 88 this.sourceGraphChanged.emit(new Patch()); | |
| 89 } | |
| 90 | |
| 91 quadCount(): number { | |
| 92 return this.store.countQuads(null, null, null, null); | |
| 93 } | |
| 94 } |