Initial commit

.gitignore

+.ccls-cache

Makefile

+
+CXX ?= g++ -O3
+
+build:
+	$(CXX) json2table.cc -std=c++17 lib/fort.c -o json2table
+
+

json2table.cc

+#include "lib/json.hpp"
+#include "lib/fort.hpp"
+#include <rlib/stdio.hpp>
+#include <rlib/opt.hpp>
+#include <algorithm>
+#include <string>
+
+using nlohmann::json;
+using std::string;
+using std::vector;
+using namespace std::literals;
+
+template <typename T, typename Allocator>
+inline void set_or_extend(std::vector<T, Allocator> &vthis, size_t index, T &&data) {
+    if(vthis.size() <= index) vthis.resize(index+1);
+    vthis[index] = std::forward<T>(data);
+}
+
+inline string json_to_string(json j) {
+    if(j.is_array()) return "ARRAY";
+    if(j.is_object()) return "OBJECT";
+    if(j.is_string()) return j.get<string>();
+    if(j.is_number_float()) return std::to_string(j.get<double>());
+    if(j.is_number()) return std::to_string(j.get<long>());
+    if(j.is_boolean()) return std::to_string(j.get<bool>());
+    if(j.is_null()) return "null";
+    return "UNKNOWN";
+}
+
+int main(int argc, char **argv) {
+    rlib::opt_parser args(argc, argv);
+    if(args.getBoolArg("-h", "--help")) {
+        rlib::println("Usage: cat xxx.json | json2table");
+        rlib::println("Usage: curl https://myapi/getJson | json2table /path/to/subobject");
+        return 1;
+    }
+
+    auto json_path = args.getSubCommand("").replace("\\", "/").strip("/");
+    json input;
+    std::cin >> input;
+    for(auto &next : json_path.split('/')) {
+        if(!next.empty())
+            input = input[next];
+    }
+
+    //////////////////////////////////////////////////////////////////////
+
+    vector<string> headers;
+    vector<vector<string>> rows(1);
+    size_t curr_row_pos = 0;
+    if(input.is_array()) {
+        for(auto &[_, item] : input.items()) {
+            if(item.is_object()) {
+                // Perfect schema: [{}, {}, ...]
+                for(auto &[key, value] : item.items()) {
+                    // Add key-value into table.
+                    auto iter = std::find(headers.cbegin(), headers.cend(), key);
+                    auto col_pos = iter - headers.cbegin();
+                    if(iter == headers.cend())
+                        headers.emplace_back(key);
+                    set_or_extend(rows[curr_row_pos], col_pos, json_to_string(value));
+                }
+            }
+            else if(item.is_array()) {
+                for(auto &[_, value] : item.items()) {
+                    rows[curr_row_pos].push_back(json_to_string(value));
+                }
+            }
+            else {
+                rows[curr_row_pos].emplace_back("VAL: "s + json_to_string(item));
+            }
+            // TABLE: end this row.
+            rows.emplace_back();
+            ++curr_row_pos;
+        }
+    }
+    else if(input.is_object()) {
+        // single-row
+        for(auto &[key, value] : input.items()) {
+            // Add key-value into table.
+            headers.emplace_back(key);
+            rows[curr_row_pos].emplace_back(json_to_string(value));
+        }
+    }
+    else {
+        // gg. Just print and go.
+        rlib::println("Single value:", json_to_string(input));
+        return 0;
+    }
+
+    // Print the table.
+    fort::char_table table;
+    table << fort::header;
+    for(auto &ele : headers) table << ele;
+    table << fort::endr;
+    for(auto &row : rows) {
+        for(auto &ele : row) table << ele;
+        table << fort::endr;
+    }
+
+    rlib::println(table.to_string());
+
+}