解析TestRail API getcases响应JSON，梳理父子ID层级关系

Hey there! Let's break down how to parse that flat JSON list from TestRail's getcases endpoint into a clear hierarchical structure—showing each top-level parent ID (where parent_id is null) and all of its nested child IDs across every level.

核心思路 #

First, we'll build a quick lookup map to link each parent ID directly to its immediate children. Then, we'll recursively (or iteratively) traverse this map to collect all descendants for each top-level parent.

示例实现（Python） #

Let's use your sample JSON to demonstrate:

1. 定义原始数据

testrail_cases = [
    {"id": 1, "parent_id": None},
    {"id": 2, "parent_id": 1},
    {"id": 6, "parent_id": None},
    {"id": 16, "parent_id": 2},
    {"id": 7, "parent_id": 1},
    {"id": 3, "parent_id": 6}
]

2. 构建父-子映射表

This step creates an O(1) lookup for any parent's direct children:

parent_map = {}
for case in testrail_cases:
    parent_id = case["parent_id"]
    case_id = case["id"]
    # Initialize empty list if parent isn't in the map yet
    if parent_id not in parent_map:
        parent_map[parent_id] = []
    parent_map[parent_id].append(case_id)

3. 递归收集所有层级的子节点

This function will dive through every nested level to gather all descendants of a given parent:

def get_all_descendants(parent_id):
    descendants = []
    # Check if the parent has direct children
    if parent_id in parent_map:
        for child_id in parent_map[parent_id]:
            descendants.append(child_id)
            # Recursively add the child's own descendants
            descendants.extend(get_all_descendants(child_id))
    return descendants

4. 生成最终的层级归属结果

We'll target only top-level parents (where parent_id is None):

hierarchical_result = {}
# Iterate over all top-level parent IDs
for top_parent_id in parent_map.get(None, []):
    hierarchical_result[top_parent_id] = get_all_descendants(top_parent_id)

# Print the result
print(hierarchical_result)

输出结果

{1: [2, 16, 7], 6: [3]}

This means:

• Top-level parent 1 has nested children: 2 (which has child 16), and 7
• Top-level parent 6 has direct child 3

可选：迭代版（避免递归栈溢出） #

If you're dealing with extremely deep hierarchies, use an iterative approach instead:

def get_all_descendants_iterative(parent_id):
    descendants = []
    stack = [parent_id]
    while stack:
        current_id = stack.pop()
        # Add all direct children of current ID
        for child_id in parent_map.get(current_id, []):
            descendants.append(child_id)
            stack.append(child_id)
    return descendants

为什么这个方法好用？ #

• Efficiency: The initial map build is O(n), and collecting descendants is also O(n) (each case is processed once)
• Scalability: Works for any number of nested levels from TestRail's API
• Clarity: The result directly maps each top-level parent to every ID under its hierarchy

内容的提问来源于stack exchange，提问作者Mahyar