接口自动化测试中，存在依赖情况：test_04的某个请求参数的值依赖test_03返回结果中的某个字段的数据，所以就需要拿到返回数据中特定字段的值。这里使用到python中的jsonpath-rw库
1、下载安装
pip install jsonpath-rw
2、导入
from jsonpath_rw import jsonpath,parse
3、例子介绍
1.返回的match数据
jsonpath_expr = parse('addCar.product') data = {'addCar':{'product': [{'id': '1','price':'38'}, {'id': '32','price':'19'}]}} print([match for match in jsonpath_expr.find(data)]) 运行结果：[DatumInContext(value=[{'id': '1', 'price': '38'}, {'id': '32', 'price': '19'}], path=Fields('product'), context=DatumInContext(value={'product': [{'id': '1', 'price': '38'}, {'id': '32', 'price': '19'}]}, path=Fields('addCar'), context=DatumInContext(value={'addCar': {'product': [{'id': '1', 'price': '38'}, {'id': '32', 'price': '19'}]}}, path=This(), context=None)))]
2.获取匹配的数据match.value
from jsonpath_rw import jsonpath,parse
data = {"addCar": {"product": [{"id": "1","price": "38"},{"id": "32", "price": "19"},]}}
jsonpath_expr = parse("addCar.product")
result = [match.value for match in jsonpath_expr.find(data)]
print(result)
运行结果： [[{'id': '1', 'price': '38'}, {'id': '32', 'price': '19'}]]
3.获取价格
from jsonpath_rw import jsonpath,parse
data = {"addCar": {"product": [{"id": "1","price": "38"},{"id": "32", "price": "19"},]}}
jsonpath_expr = parse("addCar.product[*].price")
result = [match.value for match in jsonpath_expr.find(data)]
print(result)
运行结果： ['38', '19']
官方实例
1.提取值
result = [match.value for match in jsonpath_expr.find({'foo':[{'baz':1}, {'baz':2}]})]
print(result)
>>>[1, 2]
2.获取匹配值对应的路径
from jsonpath_rw import jsonpath,parse
jsonpath_expr = parse('foo[*].baz')
result = [str(match.full_path) for match in jsonpath_expr.find({'foo': [{'baz': 1}, {'baz': 2}]})]
print(result)
>>>['foo.[0].baz', 'foo.[1].baz']
3.自动提供id
from jsonpath_rw import jsonpath,parse
result = [match.value for match in parse('foo[*].id').find({'foo': [{'id': 'bizzle'}, {'baz': 3}]})]
print(result)
>>>['bizzle']
jsonpath.auto_id_field = 'id'
result = [match.value for match in parse('foo[*].id').find({'foo': [{'id': 'bizzle'}, {'baz': 3}]})]
print(result)
>>>['foo.bizzle', 'foo.[1]']
4.扩展功能之一 命名操作符 `parent`
result = [match.value for match in parse('a.*.b.`parent`.c').find({'a': {'x': {'b': 1, 'c': 'number one'}, 'y': {'b': 2, 'c': 'number two'}}})]
print(result)
>>>['number one', 'number two']
JSONPath expressions always refer to a JSON structure in the same way as XPath expression are used in combination with an XML document. Since a JSON structure is usually anonymous and doesn't necessarily have a "root member object" JSONPath assumes the abstract name $ assigned to the outer level object.
JSONPath expressions can use the dot–notation
$.store.book[0].title
or the bracket–notation
$['store']['book'][0]['title']
for input pathes. Internal or output pathes will always be converted to the more general bracket–notation.
JSONPath allows the wildcard symbol * for member names and array indices. It borrows the descendant operator '..' from E4X and the array slice syntax proposal [start:end:step] from ECMASCRIPT 4.
Expressions of the underlying scripting language (<expr>) can be used as an alternative to explicit names or indices as in
$.store.book[(@.length-1)].title
using the symbol '@' for the current object. Filter expressions are supported via the syntax ?(<boolean expr>) as in
$.store.book[?(@.price < 10)].title
Here is a complete overview and a side by side comparison of the JSONPath syntax elements with its XPath counterparts.
| XPath | JSONPath | Description |
| / | $ | the root object/element |
| . | @ | the current object/element |
| / | . or [] | child operator |
| .. | n/a | parent operator |
| // | .. | recursive descent. JSONPath borrows this syntax from E4X. |
| * | * | wildcard. All objects/elements regardless their names. |
| @ | n/a | attribute access. JSON structures don't have attributes. |
| [] | [] | subscript operator. XPath uses it to iterate over element collections and for predicates. In Javascript and JSON it is the native array operator. |
| | | [,] | Union operator in XPath results in a combination of node sets. JSONPath allows alternate names or array indices as a set. |
| n/a | [start:end:step] | array slice operator borrowed from ES4. |
| [] | ?() | applies a filter (script) expression. |
| n/a | () | script expression, using the underlying script engine. |
| () | n/a | grouping in Xpath |
XPath has a lot more to offer (Location pathes in not abbreviated syntax, operators and functions) than listed here. Moreover there is a remarkable difference how the subscript operator works in Xpath and JSONPath.
- Square brackets in XPath expressions always operate on the node set resulting from the previous path fragment. Indices always start by 1.
- With JSONPath square brackets operate on the object or array addressed by the previous path fragment. Indices always start by 0.
Let's practice JSONPath expressions by some more examples. We start with a simple JSON structure built after an XML example representing a bookstore (original XML file).
{ "store": {
"book": [
{ "category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": 8.95
},
{ "category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": 12.99
},
{ "category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": 8.99
},
{ "category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": 22.99
}
],
"bicycle": {
"color": "red",
"price": 19.95
}
}
}
| XPath | JSONPath | Result |
/store/book/author |
$.store.book[*].author |
the authors of all books in the store |
//author |
$..author |
all authors |
/store/* |
$.store.* |
all things in store, which are some books and a red bicycle. |
/store//price |
$.store..price |
the price of everything in the store. |
//book[3] |
$..book[2] |
the third book |
//book[last()] |
$..book[(@.length-1)]$..book[-1:] |
the last book in order. |
//book[position()<3] |
$..book[0:1]$..book[:2] |
the first two books |
//book[isbn] |
$..book[?(@.isbn)] |
filter all books with isbn number |
//book[price<10] |
$..book[?(@.price<10)] |
filter all books cheapier than 10 |
//* |
$..* |
all Elements in XML document. All members of JSON structure. |
上面是JSONPATH和XPath的一些对比，亲自试了几个，标黄的几个没跑通，大家可以在下面探讨一下
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