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Just a question. How does JSON and JSONSchema deal with graph structure? For example, what happens when your data structure in memory is A->B->C->A. And you wan

by lolive 10y ago

Just a question. How does JSON and JSONSchema deal with graph structure? For example, what happens when your data structure in memory is A->B->C->A. And you want to serialize/deserialize such a data structure. (as far as i undestand, the JSON serialization of this graph would have duplicated A, once a top level and once inside the serialization of C).

akst 10y ago
You can probably encode a directed graph by storing the nodes as values in a dictionary which track which nodes they point too, and the keys of the dictionary would be the node identifiers. If you represent it a specific way in your program, just perform a normalisation phase after decoding, and vice versa for encoding.
- lolive 10y ago
  As far as I understand, this is the way RDF works. I use N3.js and it basically does that. Is it a need that usually appears when you send JSON between server and client?
  - akst 10y ago
    Not sure what the requirements are for the parent comment, I'm just explaining an approach to serialise a graph data structure.
msoad 10y ago
Look up json pointers and you will be enlightened
bcherny 10y ago
JSONSchema has a concept of "$refs", which is a way to encode a pointer to a value in a JSONSchema. $refs can point to another node in the same graph, a node in another JSONSchema on the same filesystem, or a node in another JSONSchema fetched over the network. $refs are used in JSONSchema, but are described in the separate JSONPointer spec [0]. See unit tests for examples: - In-file $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.2.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Local $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.1.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Remote $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.3.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Cyclical $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/refWithCycle.1.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... Hope that helps! [0] https://tools.ietf.org/html/rfc6901 https://tools.ietf.org/html/rfc6901

by lolive 10y ago

akst 10y ago

You can probably encode a directed graph by storing the nodes as values in a dictionary which track which nodes they point too, and the keys of the dictionary would be the node identifiers. If you represent it a specific way in your program, just perform a normalisation phase after decoding, and vice versa for encoding.

lolive 10y ago
As far as I understand, this is the way RDF works. I use N3.js and it basically does that. Is it a need that usually appears when you send JSON between server and client?
- akst 10y ago
  Not sure what the requirements are for the parent comment, I'm just explaining an approach to serialise a graph data structure.

msoad 10y ago

Look up json pointers and you will be enlightened

bcherny 10y ago

JSONSchema has a concept of "$refs", which is a way to encode a pointer to a value in a JSONSchema. $refs can point to another node in the same graph, a node in another JSONSchema on the same filesystem, or a node in another JSONSchema fetched over the network. $refs are used in JSONSchema, but are described in the separate JSONPointer spec [0]. See unit tests for examples: - In-file $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.2.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Local $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.1.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Remote $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/ref.3.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... - Cyclical $ref: https://github.com/bcherny/json-schema-to-typescript/blob/master/test/e2e/refWithCycle.1.ts https://github.com/bcherny/json-schema-to-typescript/blob/ma... Hope that helps! [0] https://tools.ietf.org/html/rfc6901 https://tools.ietf.org/html/rfc6901