forked from bblanchon/ArduinoJson
Rewrote example JsonHttpClient.ino (fixes #600)
This commit is contained in:
Benoit Blanchon
10
CHANGELOG.md
10
CHANGELOG.md
@ -1,6 +1,10 @@
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ArduinoJson: change log
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=======================
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HEAD
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----
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* Rewrote example `JsonHttpClient.ino` (issue #600)
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v5.11.2
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-------
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@ -45,20 +49,20 @@ v5.10.0
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### BREAKING CHANGES :warning:
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| Old syntax | New syntax |
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|---------------------------------|---------------------|
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|:--------------------------------|:--------------------|
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| `double_with_n_digits(3.14, 2)` | `3.14` |
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| `float_with_n_digits(3.14, 2)` | `3.14f` |
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| `obj.set("key", 3.14, 2)` | `obj["key"] = 3.14` |
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| `arr.add(3.14, 2)` | `arr.add(3.14)` |
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| Input | Old output | New output |
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|-----------|------------|------------|
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|:----------|:-----------|:-----------|
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| `3.14159` | `3.14` | `3.14159` |
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| `42.0` | `42.00` | `42` |
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| `0.0` | `0.00` | `0` |
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| Expression | Old result | New result |
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|--------------------------------|------------|------------|
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|:-------------------------------|:-----------|:-----------|
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| `JsonVariant(42).is<int>()` | `true` | `true` |
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| `JsonVariant(42).is<float>()` | `false` | `true` |
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| `JsonVariant(42).is<double>()` | `false` | `true` |
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@ -1,181 +1,86 @@
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// Sample Arduino Json Web Client
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// Downloads and parse http://jsonplaceholder.typicode.com/users/1
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//
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// ArduinoJson - arduinojson.org
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// Copyright Benoit Blanchon 2014-2017
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// MIT License
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//
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// Example of an HTTP client parsing a JSON response.
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//
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// This program perform an HTTP GET of arduinojson.org/example.json
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// Here is the expected response:
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// {
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// "sensor": "gps",
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// "time": 1351824120,
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// "data": [
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// 48.756080,
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// 2.302038
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// ]
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// }
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// See http://arduinojson.org/assistant/ to compute the size of the buffer.
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//
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// Disclaimer: the code emphasize the communication between client and server,
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// it doesn't claim to be a reference of good coding practices.
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#include <ArduinoJson.h>
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#include <Ethernet.h>
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#include <SPI.h>
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EthernetClient client;
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const char* server = "jsonplaceholder.typicode.com"; // server's address
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const char* resource = "/users/1"; // http resource
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const unsigned long BAUD_RATE = 9600; // serial connection speed
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const unsigned long HTTP_TIMEOUT = 10000; // max respone time from server
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const size_t MAX_CONTENT_SIZE = 512; // max size of the HTTP response
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// The type of data that we want to extract from the page
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struct UserData {
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char name[32];
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char company[32];
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};
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// ARDUINO entry point #1: runs once when you press reset or power the board
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void setup() {
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initSerial();
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initEthernet();
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}
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Serial.begin(9600);
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while (!Serial);
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// ARDUINO entry point #2: runs over and over again forever
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void loop() {
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if (connect(server)) {
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if (sendRequest(server, resource) && skipResponseHeaders()) {
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UserData userData;
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if (readReponseContent(&userData)) {
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printUserData(&userData);
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}
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}
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}
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disconnect();
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wait();
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}
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// Initialize Serial port
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void initSerial() {
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Serial.begin(BAUD_RATE);
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while (!Serial) {
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; // wait for serial port to initialize
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}
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Serial.println("Serial ready");
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}
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// Initialize Ethernet library
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void initEthernet() {
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echo("Initialize Ethernet library");
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byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
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if (!Ethernet.begin(mac)) {
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Serial.println("Failed to configure Ethernet");
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return;
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}
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Serial.println("Ethernet ready");
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Ethernet.begin(mac) || die("Failed to configure Ethernet");
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delay(1000);
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}
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// Open connection to the HTTP server
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bool connect(const char* hostName) {
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Serial.print("Connect to ");
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Serial.println(hostName);
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echo("Connect to HTTP server");
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EthernetClient client;
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client.setTimeout(10000);
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client.connect("arduinojson.org", 80) || die("Connection failed");
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bool ok = client.connect(hostName, 80);
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Serial.println(ok ? "Connected" : "Connection Failed!");
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return ok;
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}
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// Send the HTTP GET request to the server
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bool sendRequest(const char* host, const char* resource) {
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Serial.print("GET ");
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Serial.println(resource);
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client.print("GET ");
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client.print(resource);
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client.println(" HTTP/1.0");
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client.print("Host: ");
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client.println(host);
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echo("Send HTTP request");
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client.println("GET /example.json HTTP/1.0");
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client.println("Host: arduinojson.org");
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client.println("Connection: close");
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client.println();
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client.println() || die("Failed to send request");
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return true;
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echo("Check HTTP status");
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char status[32] = {0};
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client.readBytesUntil('\r', status, sizeof(status));
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if (strcmp(status, "HTTP/1.1 200 OK") != 0) {
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echo(status);
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die("Unexpected HTTP response");
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}
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// Skip HTTP headers so that we are at the beginning of the response's body
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bool skipResponseHeaders() {
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// HTTP headers end with an empty line
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echo("Skip HTTP headers");
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char endOfHeaders[] = "\r\n\r\n";
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client.find(endOfHeaders) || die("Invalid response");
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client.setTimeout(HTTP_TIMEOUT);
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bool ok = client.find(endOfHeaders);
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if (!ok) {
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Serial.println("No response or invalid response!");
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}
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return ok;
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}
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// Parse the JSON from the input string and extract the interesting values
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// Here is the JSON we need to parse
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// {
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// "id": 1,
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// "name": "Leanne Graham",
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// "username": "Bret",
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// "email": "Sincere@april.biz",
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// "address": {
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// "street": "Kulas Light",
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// "suite": "Apt. 556",
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// "city": "Gwenborough",
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// "zipcode": "92998-3874",
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// "geo": {
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// "lat": "-37.3159",
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// "lng": "81.1496"
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// }
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// },
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// "phone": "1-770-736-8031 x56442",
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// "website": "hildegard.org",
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// "company": {
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// "name": "Romaguera-Crona",
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// "catchPhrase": "Multi-layered client-server neural-net",
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// "bs": "harness real-time e-markets"
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// }
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// }
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bool readReponseContent(struct UserData* userData) {
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// Compute optimal size of the JSON buffer according to what we need to parse.
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// See http://arduinojson.org/assistant/
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const size_t BUFFER_SIZE =
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JSON_OBJECT_SIZE(8) // the root object has 8 elements
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+ JSON_OBJECT_SIZE(5) // the "address" object has 5 elements
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+ JSON_OBJECT_SIZE(2) // the "geo" object has 2 elements
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+ JSON_OBJECT_SIZE(3) // the "company" object has 3 elements
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+ MAX_CONTENT_SIZE; // additional space for strings
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// Allocate a temporary memory pool
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echo("Allocate JsonBuffer");
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const size_t BUFFER_SIZE = JSON_OBJECT_SIZE(3) + JSON_ARRAY_SIZE(2) + 60;
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DynamicJsonBuffer jsonBuffer(BUFFER_SIZE);
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echo("Parse JSON object");
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JsonObject& root = jsonBuffer.parseObject(client);
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if (!root.success()) die("Parsing failed!");
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if (!root.success()) {
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Serial.println("JSON parsing failed!");
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return false;
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}
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echo("Extract values");
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echo(root["sensor"].as<char*>());
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echo(root["time"].as<char*>());
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echo(root["data"][0].as<char*>());
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echo(root["data"][1].as<char*>());
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// Here were copy the strings we're interested in
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strcpy(userData->name, root["name"]);
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strcpy(userData->company, root["company"]["name"]);
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// It's not mandatory to make a copy, you could just use the pointers
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// Since, they are pointing inside the "content" buffer, so you need to make
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// sure it's still in memory when you read the string
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return true;
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}
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// Print the data extracted from the JSON
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void printUserData(const struct UserData* userData) {
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Serial.print("Name = ");
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Serial.println(userData->name);
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Serial.print("Company = ");
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Serial.println(userData->company);
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}
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// Close the connection with the HTTP server
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void disconnect() {
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Serial.println("Disconnect");
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echo("Disconnect");
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client.stop();
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}
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// Pause for a 1 minute
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void wait() {
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Serial.println("Wait 60 seconds");
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delay(60000);
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void loop() {}
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void echo(const char* message) {
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Serial.println(message);
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}
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bool die(const char* message) {
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Serial.println(message);
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while (true); // loop forever
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return false;
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}
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