SOLVED Could someone translate this Javascript API to Lazarus/FP please

[Ten_Mile_Hike]

As the Subject states.
---I'm using Win10 + Latest Laz release

Code: Javascript  [Select][+][-]

1. const endpoint = "https://earthquake.usgs.gov/fdsnws/event/1/query";
2. // Set query parameters
3. const params = {
4.   starttime: "2021-01-01",
5.   endtime: "2021-02-01",
6.   minmagnitude: 6.0,
7.   latitude: 34.0522,
8.   longitude: -118.2437,
9.   maxradiuskm: 1000,
10.   orderby: "time"
11. };
12.  
13. // Construct query string
14. const queryString = Object.keys(params)
15.   .map(key => key + "=" + encodeURIComponent(params[key]))
16.   .join("&");
17.  
18. // Make API request with fetch
19. fetch(endpoint + "?" + queryString)
20.   .then(response => response.json())
21.   .then(data => {
22.     console.log(data);
23.   });

[jamie]

Go here and study.
https://wiki.lazarus.freepascal.org/fphttpclient
Install the "fpWeb" and you can use the TFpHttpClient.

[TRon]

Perhaps the following approach will suffice.

Note that there is no error checking (which is really mandatory) thus would have to implement that yourself and I left the encoding as an exercise (FPC does not seem to come shipped with (proper) parameter encoding.

Code: Pascal  [Select][+][-]

1. const
2.   endpoint = 'https://earthquake.usgs.gov/fdsnws/event/1/query';
3.  
4.   params =
5.   '{' +
6.    '"starttime": "2021-01-01",' +
7.    '"endtime": "2021-02-01",' +
8.    '"minmagnitude": 6.0,' +
9.    '"latitude": 34.0522,' +
10.    '"longitude": -118.2437,' +
11.    '"maxradiuskm": 1000,' +
12.    '"orderby": "time"' +
13.   '}';
14.  
15. function fetch(const aURL: string): string;
16. var
17.   Client: TFPHTTPClient;
18. begin
19.   fetch:= '';
20.   Client:= TFPHTTPClient.Create(nil);
21.   try
22.     CLient.AllowRedirect:= true;
23.     fetch:= Client.Get(aURL);
24.   finally
25.     Client.Free;
26.   end;
27. end;
28.  
29. function encodeURIComponent(const aComponent: string): string;
30. begin
31.   // TODO: properly encode URI component.
32.   // See also:
33.   // - https://en.wikipedia.org/wiki/Uniform_Resource_Identifier
34.   // - https://en.wikipedia.org/wiki/Query_string#URL_encoding
35.   encodeURIComponent:= aComponent;
36. end;
37.  
38. function Params2Query(const aParams: string): string;
39. var
40.   JSONParams: TJSONData;
41.   JSONParam: TJSONEnum;
42.   key, value: string;
43. begin
44.   Params2Query:= '';
45.   JSONParams:= getJSON(aParams);
46.  
47.   for JSONParam in JSONParams do
48.   begin
49.     key:= JSONParam.Key;
50.     case JSONParam.value.JSONType of
51.       jtNumber, jtstring, jtboolean: Writestr(value, JSONParam.Value.Value);
52.       else value:= '';
53.     end;
54.     Params2Query:= Params2Query + JSONParam.Key + '=' + encodeURIComponent(value);
55.     if JSONParam.KeyNum < pred(JSONParams.Count)
56.       then Params2Query := Params2Query + '&';
57.   end;
58.  
59.   JSONParams.Free;
60. end;
61.  
62. var
63.   queryString: string;
64.   response: string;
65.   responseAsJSON: TJSONData;
66. begin
67.   queryString:= Params2Query(params);
68.   response:= fetch(endpoint + '?' + queryString);
69.   responseAsJSON:= getJSON(response);
70.   writeln(responseAsJSON.FormatJSON);
71.   responseAsJSON.Free;
72. end.
73.  

[Ten_Mile_Hike]

Thank you TRon and Jamie.

[Dzandaa]

Hi,

I wrote this little program to show earthquakes with LazMapViewer. Feel free to modify it (correct it )

There maybe/surely be unfreed memory

The Right button mark the center (Lat. Long) of the search.
The Middle button Show Info when clicking on an earthquake.
The Left button is panning and the middle wheel for Zooming.

Try to limit your search to 50-100km .

Have a nice day.

B->

[jamie]

is that one of those things you need a registration key from google ?

[Dzandaa]

Hi,

No registration key.

I use:

https://earthquake.usgs.gov/earthquakes/map/?extent=47.37975,-110.85754&extent=50.50295,-103.38684

B->

[jamie]

Hmm, that gives me an idea to add to a program I have here used on Ham Radio!