40 lines
1.2 KiB
C++
40 lines
1.2 KiB
C++
#include <iostream>
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#include <nlohmann/json_view.hpp>
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using json_document = nlohmann::json_document;
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using json_pointer = nlohmann::json::json_pointer;
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int main()
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{
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// "retry_of" is only present on some records, nested a level down
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// inside "meta"
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json_document batch = json_document::parse(R"(
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[
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{"id": 1, "meta": {}},
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{"id": 2, "meta": {"retry_of": 1}}
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]
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)");
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const auto records = batch.root();
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const json_pointer retry_of("/meta/retry_of");
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for (std::size_t i = 0; i < records.size(); ++i)
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{
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const auto record = records[i];
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if (record.contains(retry_of))
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{
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std::cout << "record " << i << " is a retry of " << record[retry_of].get<int>() << '\n';
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}
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else
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{
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std::cout << "record " << i << " is original\n";
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}
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}
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// contains() with a JSON pointer never throws -- not even for a
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// pointer that indexes into a primitive ("/0/id/x") or uses a
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// malformed array index ("/01"), either of which would need a
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// try/catch with json::contains(ptr)
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std::cout << std::boolalpha << records.contains(json_pointer("/0/id/x")) << '\n';
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std::cout << std::boolalpha << records.contains(json_pointer("/01")) << '\n';
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}
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