I've been trying to send a base64 image using java
to NodeJS
API, after working and searching for hours I could not know what might cause the following problem, the problem as following:
After logging the base64 image in nodejs I see all
+
chars replaced byspace
Here's a part of the original base64 in Java
f8A0NH2qH+/+hooouAfaof7/wCho+1Q/
and here's is a part of the received image in NodeJS
f8A0NH2qH / hooouAfaof7/wCho 1Q/
I've tried to send an image via POSTMAN
and no problem at all.
All steps as following:
1- I am converting an image to base64 using the following snippet
public static String imgToBase64String(final RenderedImage img, final String formatName) {
final ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
ImageIO.write(img, formatName, Base64.getEncoder().wrap(os));
return os.toString(StandardCharsets.ISO_8859_1.name());
} catch (final IOException ioe) {
throw new UncheckedIOException(ioe);
}
}
public static BufferedImage base64StringToImg(final String base64String) {
try {
return ImageIO.read(new ByteArrayInputStream(Base64.getDecoder().decode(base64String)));
} catch (final IOException ioe) {
throw new UncheckedIOException(ioe);
}
}
And to take screenshot
final Robot robot = new Robot();
final Rectangle r = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
final BufferedImage bi = robot.createScreenCapture(r);
final String base64String = Base64Converter.imgToBase64String(bi, "jpg");
2- I am using Gson
library to stringify object
3- I am using bodyParser
in NodeJS
4- Sending HTTP
request as:
public static void sendPOST(String image) throws Exception {
String POST_PARAMS = "screenShotData";
URL obj = new URL(POST_URL);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
con.setRequestMethod("POST");
con.setConnectTimeout(5000); // 5 seconds
con.setReadTimeout(5000); // 5 seconds
Gson gson = new Gson();
Http.ScreenShot screenShot = new ScreenShot(); // This is just a class with a string property
screenShot.setImage(image);
POST_PARAMS += gson.toJsonTree(screenShot).getAsJsonObject();
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
byte[] outputBytesArray = POST_PARAMS.getBytes();
os.write(outputBytesArray);
os.flush();
os.close();
int responseCode = con.getResponseCode();
System.out.println("POST Response Code :: " + responseCode);
if (responseCode == HttpURLConnection.HTTP_OK) { //success
BufferedReader in = new BufferedReader(new InputStreamReader(
con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
Object responseObject = gson.fromJson(response.toString(), Object.class);
System.out.println("Res: " + responseObject);
} else {
System.out.println(con.getResponseMessage());
}
}
In URL encoded text, the +
character means a space character. For example,
https://example.com/?s=nodejs+bodyparser
sends the s
parameter with the value
nodejs bodyparser
(notice the space).
When you do an ordinary form post (the kind browsers do) you use the application/x-www-form-urlencoded
data type, meaning the payload of your POST operation looks like a query string. I think you are passing a JSON object as a text string without url-encoding it.
You probably want to use the application/json
data type instead. nodejs's body parser detects, from your Content-type header, that it's JSON and parses it correctly.
Try this. (not debugged, sorry.)
string payload = gson.toJsonTree(screenShot).getAsJsonObject();
byte[] outputBytesArray = payload.getBytes();
con.setRequestProperty("Content-Type", "application/json");
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
os.write(outputBytesArray);
os.flush();
os.close();