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73 lines
2.2 KiB
73 lines
2.2 KiB
3 years ago
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// ArduinoJson - https://arduinojson.org
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// Copyright Benoit Blanchon 2014-2021
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// MIT License
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//
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// This example shows the different ways you can use Flash strings with
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// ArduinoJson.
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//
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// Use Flash strings sparingly, because ArduinoJson duplicates them in the
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// JsonDocument. Prefer plain old char*, as they are more efficient in term of
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// code size, speed, and memory usage.
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//
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// https://arduinojson.org/v6/example/progmem/
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#include <ArduinoJson.h>
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void setup() {
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#ifdef PROGMEM // <- check that Flash strings are supported
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DynamicJsonDocument doc(1024);
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// You can use a Flash String as your JSON input.
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// WARNING: the strings in the input will be duplicated in the JsonDocument.
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deserializeJson(doc, F("{\"sensor\":\"gps\",\"time\":1351824120,"
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"\"data\":[48.756080,2.302038]}"));
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JsonObject obj = doc.as<JsonObject>();
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// You can use a Flash String to get an element of a JsonObject
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// No duplication is done.
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long time = obj[F("time")];
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// You can use a Flash String to set an element of a JsonObject
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// WARNING: the content of the Flash String will be duplicated in the
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// JsonDocument.
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obj[F("time")] = time;
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// You can set a Flash String to a JsonObject or JsonArray:
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// WARNING: the content of the Flash String will be duplicated in the
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// JsonDocument.
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obj["sensor"] = F("gps");
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// It works with serialized() too:
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obj["sensor"] = serialized(F("\"gps\""));
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obj["sensor"] = serialized(F("\xA3gps"), 3);
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// You can compare the content of a JsonVariant to a Flash String
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if (obj["sensor"] == F("gps")) {
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// ...
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}
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#else
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#warning PROGMEM is not supported on this platform
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#endif
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}
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void loop() {
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// not used in this example
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}
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// See also
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// --------
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//
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// https://arduinojson.org/ contains the documentation for all the functions
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// used above. It also includes an FAQ that will help you solve any memory
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// problem.
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//
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// The book "Mastering ArduinoJson" contains a quick C++ course that explains
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// how your microcontroller stores strings in memory. It also tells why you
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// should not abuse Flash strings with ArduinoJson.
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// Learn more at https://arduinojson.org/book/
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// Use the coupon code TWENTY for a 20% discount ❤❤❤❤❤
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