Good Afternoon;
I’m running into an issue, and I am unsure as to why I am getting a 503 Service Unavailable error.
For starters, I know I’m hitting the API endpoint (https://api.openrouteservice.org/v2/isochrones/driving-car) and that the endpoint is active because I can see the errors in the dashboard side (14 errors today and counting trying to sort this out myself).
I also know that the API key is correct and being received because I would get 403 errors before I put in a proper API key, so I know I’m hitting the right spot.
Now, as for the problem, I think based on my bloodied and bleary forehead that the issue lies in the parameters I’m trying to send to the API which are a straight copy from the Javascript SDK, so I’ll go into details regarding how exactly I’m doing that.
First of all though, I’m operating on a modification of the Javascript SDK source files, stripping out the NPM components (Bluebird and Superagent) and instead pushing the negotiation portion between servers to the C# back-end to deal with the CORS issue that comes from trying to send raw AJAX to another server.
That looks something like this (in the _layout.cshtml partial that loads to every page that uses it):
<script type="module" src="~/lib/ORS/src/OrsBase.js"></script>
<script type="module">
import OrsUtil from "@Url.Content("~/lib/ORS/src/OrsUtil.js")";
import OrsInput from "@Url.Content("~/lib/ORS/src/OrsInput.js")";
import OrsGeocode from "@Url.Content("~/lib/ORS/src/OrsGeocode.js")";
import OrsIsochrones from "@Url.Content("~/lib/ORS/src/OrsIsochrones.js")";
import OrsDirections from "@Url.Content("~/lib/ORS/src/OrsDirections.js")";
import OrsMatrix from "@Url.Content("~/lib/ORS/src/OrsMatrix.js")";
import OrsPois from "@Url.Content("~/lib/ORS/src/OrsPois.js")";
import OrsElevation from "@Url.Content("~/lib/ORS/src/OrsElevation.js")";
import OrsOptimization from "@Url.Content("~/lib/ORS/src/OrsOptimization.js")";
const Openrouteservice = {
Util: OrsUtil,
Input: OrsInput,
Geocode: OrsGeocode,
Isochrones: OrsIsochrones,
Directions: OrsDirections,
Matrix: OrsMatrix,
Pois: OrsPois,
Elevation: OrsElevation,
Optimization: OrsOptimization
};
if (typeof module === "object" && typeof module.exports === "object") {
module.exports = Openrouteservice;
} else if (typeof define === "function" && define.amd) {
define(Openrouteservice);
}
if (typeof window !== "undefined") {
window.Openrouteservice = Openrouteservice;
}
export {
Openrouteservice as default
};
</script>
<script src="~/js/site.js" asp-append-version="true"></script>
@await RenderSectionAsync("Scripts", required: false)
Then, in my Index.cshtml, I am throwing the Isochrone test content from the Javascript SDK, which looks something like this:
<div class="text-center">
<h1 class="display-4">Welcome</h1>
<p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
<h1>ORS-js lib examples</h1>
<section>
<h2>Isochrones</h2>
<div id="isochrones"></div>
</section>
</div>
@section Scripts{
<script type='module'>
window.onload = function () {
const node = document.getElementById("isochrones")
const Isochrones = new Openrouteservice.Isochrones({
api_key: apiKey
})
Isochrones.calculate({
profile: 'driving-car',
locations: [[8.681495, 49.41461], [8.686507, 49.41943]],
range: [300, 200],
area_units: 'km'
})
.then(function (json) {
let response = JSON.stringify(json, null, "\t")
console.log(response);
response = response.replace(/(\n)/g, '<br>');
response = response.replace(/(\t)/g, ' ');
node.innerHTML = "<h3>Response</h3><p>" + response + "</p>";
})
.catch(function (err) {
let response = JSON.stringify(err, null, "\t")
console.log(response);
response = response.replace(/(\n)/g, '<br>');
response = response.replace(/(\t)/g, ' ');
node.innerHTML = "<h3>Response</h3><p>" + response + "</p>";
})
}
</script>
}
Then, I altered the OrsBase.js file to stop calling it’s own cross-domain call and instead call an internal function (because of CORS and removing the NPM requirements) (NOTE: I am only calling console.logs at the moment because I want to see the result data before I start working on shunting it back to where it goes using resolve / reject)
createRequest(body, resolve, reject) {
let url = orsUtil.prepareUrl(this.argsCache)
if (this.argsCache[Constants.propNames.service] === 'pois') {
url += url.indexOf('?') > -1 ? '&' : '?'
}
const timeout = this.defaultArgs[Constants.propNames.timeout] || 10000
//Calling C# level section to handle CORS issues
$.ajax({
type: "POST",
url: baseUrl + "Home/getORS",
async: true,
dataType: 'json',
data: {
"url": url,
"args": JSON.stringify(this.customHeaders),
"body": JSON.stringify(body)
},
timeout: timeout,
success: function (data) {
console.log(data);
},
error: function (jqXHR, textStatus, errorThrown) {
console.error(jqXHR);
},
complete: function (jqXHR, textStatus) {
console.log(jqXHR);
}
});
}
The actual API call is handled currently in the controller, but will eventually be moved into a model for production, that looks something like this:
public async Task<IActionResult> getORS(string url, string args, string body)
{
Uri? uriResult;
bool result = Uri.TryCreate(url, UriKind.Absolute, out uriResult) && (uriResult.Scheme == Uri.UriSchemeHttp || uriResult.Scheme == Uri.UriSchemeHttps);
if (!result)
{
return Json("");
}
HttpClient client = new HttpClient();
WebApplicationBuilder builder = WebApplication.CreateBuilder();
string apiKey = builder.Configuration.GetSection("ORS")["apiKey"];
HttpRequestMessage request = new HttpRequestMessage
{
Method = HttpMethod.Post,
RequestUri = uriResult,
Headers = {
{ HttpRequestHeader.Authorization.ToString(), apiKey },
{ HttpRequestHeader.Accept.ToString(), "application/json" },
},
Content = new StringContent(body, System.Text.Encoding.UTF8, "application/json")
};
if (args != "[]")
{
foreach (KeyValuePair<string, string> val in JsonConvert.DeserializeObject<Dictionary<string, string>>(args))
{
request.Headers.Add(val.Key, val.Value);
}
}
var response = await client.SendAsync(request).ConfigureAwait(false);
try
{
response.EnsureSuccessStatusCode();
return Json(await response.Content.ReadAsStringAsync().ConfigureAwait(false));
}
catch (Exception ex)
{
var returnVal = new { returnStatusCode = response.StatusCode, reason = response.ReasonPhrase };
return Json(returnVal);
}
}
So, as you can see, I am calling the Isochrone builder, going through and polling the data, and when I hit the HTTPRequest, it’s firing back the 503.
Additionally, when there was another value (at one point I had altitude and manually re-created the object that is being passed up from the test front-end) for altitude which caused the API to return a 406 error because it wasn’t expecting the variable.
From the console in the browser, the body, before it is turned into a JSON string, looks like this:
{
"locations": [
[
8.681495,
49.41461
],
[
8.686507,
49.41943
]
],
"range": [
300,
200
],
"area_units": "km"
}
And that comes through to the controller as a string like so:
{"locations":[[8.681495,49.41461],[8.686507,49.41943]],"range":[300,200],"area_units":"km"}
So, the question is, what is missing, misconfigured, or wrong with this data I’m sending as the body of the HttpRequestMessage content?