camel-language-jsonpath 0.5.7

JSONPath Language for rust-camel (RFC 9535)
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

# camel-language-jsonpath

> JSONPath Language for rust-camel YAML DSL

## Overview

`camel-language-jsonpath` implements [RFC 9535 JSONPath](https://datatracker.ietf.org/doc/html/rfc9535) — a query language for extracting values from JSON data.

## Supported JSONPath Syntax

| Syntax | Description | Example |
|--------|-------------|---------|
| `$` | Root node | `$` |
| `.field` | Child member | `$.store.name` |
| `['field']` | Child member (quoted) | `$['store']['name']` |
| `[index]` | Array index | `$.items[0]` |
| `[start:end]` | Array slice | `$.items[0:5]` |
| `[*]` | Wildcard (all items) | `$.items[*]` |
| `..field` | Descendant (deep scan) | `$..price` |
| `?()` | Filter expression | `$.items[?(@.price > 10)]` |
| `,` | Union (multiple names/indices) | `$.items[0,2,4]` |
| `()` | Script expression | `$.items[(@.length - 1)]` |

> **Note:** JSONPath expressions operate on the message body. The body must be JSON or coercible to JSON. Text bodies containing valid JSON strings are automatically parsed.

## Feature Enablement

Enable in `Cargo.toml`:

```toml
[dependencies.camel-core]
version = "0.5"
features = ["lang-jsonpath"]
```

## YAML DSL Usage

### Filter

```yaml
routes:
  - id: "filter-high-price"
    from: "direct:orders"
    filter:
      jsonpath: "$.items[?(@.price > 100)]"
    steps:
      - to: "log:high-value"
```

### Set Header

```yaml
routes:
  - id: "set-header-from-json"
    from: "direct:data"
    set-header:
      name: "customer-id"
      expression:
        language: "jsonpath"
        expression: "$.customer.id"
    steps:
      - to: "log:info"
```

### Set Body

```yaml
routes:
  - id: "set-body-from-json"
    from: "direct:data"
    set-body:
      expression:
        language: "jsonpath"
        expression: "$.result"
    steps:
      - to: "log:info"
```

### Log

```yaml
routes:
  - id: "log-json-value"
    from: "direct:data"
    log:
      message: "Price: ${jsonpath:$.price}"
      logging-level: "info"
```

### Split

```yaml
routes:
  - id: "split-array"
    from: "direct:items"
    split:
      expression:
        language: "jsonpath"
        expression: "$.items[*]"
    steps:
      - to: "log:item"
```

### Choice

```yaml
routes:
  - id: "choice-by-type"
    from: "direct:orders"
    choice:
      - when:
          jsonpath: "$.type == 'premium'"
        steps:
          - to: "log:premium"
      - otherwise:
          steps:
            - to: "log:standard"
```

## Usage

```rust
use camel_language_jsonpath::JsonPathLanguage;
use camel_language_api::Language;

let lang = JsonPathLanguage;

// Create a predicate
let pred = lang.create_predicate("$.items[?(@.price > 10)]").unwrap();

// Create an expression
let expr = lang.create_expression("$.store.name").unwrap();
```

## Registration

`JsonPathLanguage` is registered in `CamelContext` under the name `"jsonpath"` when the `lang-jsonpath` feature is enabled:

```rust
let mut ctx = CamelContext::new();
// JsonPathLanguage available as "jsonpath"
let lang = ctx.resolve_language("jsonpath").unwrap();
```

## License

Apache-2.0