public static async Task <IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", "post", "put", "patch", Route = "fhir/{res}/{id?}")] HttpRequest req,
ILogger log, ClaimsPrincipal principal, string res, string id)
{
/* Load the request contents */
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
/* Get/update/check current bearer token to authenticate the proxy to the FHIR Server
* The following parameters must be defined in environment variables:
* FS_URL = the fully qualified URL to the FHIR Server
* FS_TENANT_NAME = the GUID or UPN of the AAD tenant that is hosting FHIR Server Authentication
* FS_CLIENT_ID = the client or app id of the private client authorized to access the FHIR Server
* FS_SECRET = the client secret to pass to FHIR Server Authentication
* FS_RESOURCE = the audience or resource for the FHIR Server for Azure API for FHIR should be https://azurehealthcareapis.com
*/
if (!string.IsNullOrEmpty(System.Environment.GetEnvironmentVariable("FS_CLIENT_ID")) && (_bearerToken == null || FHIRClient.isTokenExpired(_bearerToken)))
{
lock (_lock)
{
log.LogInformation($"Obtaining new OAUTH2 Bearer Token for access to FHIR Server");
_bearerToken = FHIRClient.GetOAUTH2BearerToken(System.Environment.GetEnvironmentVariable("FS_TENANT_NAME"), System.Environment.GetEnvironmentVariable("FS_RESOURCE"),
System.Environment.GetEnvironmentVariable("FS_CLIENT_ID"), System.Environment.GetEnvironmentVariable("FS_SECRET"));
}
}
/*
* Create User Custom Headers these headers are passed to the FHIR Server to communicate credentials of the authorized user for each proxy call
* this is ensures accruate audit trails for FHIR server access. Note: This headers are honored by the Azure API for FHIR Server
*/
List <HeaderParm> auditheaders = new List <HeaderParm>();
auditheaders.Add(new HeaderParm("X-MS-AZUREFHIR-AUDIT-PROXY", "FHIREventProcessor"));
/* Preserve FHIR Specific change control headers and include in the proxy call */
List <HeaderParm> customandrestheaders = new List <HeaderParm>();
foreach (string key in req.Headers.Keys)
{
string s = key.ToLower();
if (s.Equals("etag"))
{
customandrestheaders.Add(new HeaderParm(key, req.Headers[key].First()));
}
else if (s.StartsWith("if-"))
{
customandrestheaders.Add(new HeaderParm(key, req.Headers[key].First()));
}
}
/* Add User Audit Headers */
customandrestheaders.AddRange(auditheaders);
/* Get a FHIR Client instance to talk to the FHIR Server */
log.LogInformation($"Instanciating FHIR Client Proxy");
FHIRClient fhirClient = new FHIRClient(System.Environment.GetEnvironmentVariable("FS_URL"), _bearerToken);
FHIRResponse fhirresp = null;
/* Proxy the call to the FHIR Server */
JObject result = null;
if (req.Method.Equals("GET"))
{
var qs = req.QueryString.HasValue ? req.QueryString.Value : null;
fhirresp = fhirClient.LoadResource(res + (id == null ? "" : "/" + id), qs, false, customandrestheaders.ToArray());
}
else
{
fhirresp = fhirClient.SaveResource(requestBody, req.Method, customandrestheaders.ToArray());
}
/* Fix location header to proxy address */
if (fhirresp.Headers.ContainsKey("Location"))
{
fhirresp.Headers["Location"].Value = fhirresp.Headers["Location"].Value.Replace(Environment.GetEnvironmentVariable("FS_URL"), req.Scheme + "://" + req.Host.Value + req.Path.Value.Substring(0, req.Path.Value.IndexOf(res) - 1));
}
var str = fhirresp.Content == null ? "" : (string)fhirresp.Content;
/* Fix server locations to proxy address */
str = str.Replace(Environment.GetEnvironmentVariable("FS_URL"), req.Scheme + "://" + req.Host.Value + req.Path.Value.Substring(0, req.Path.Value.IndexOf(res) - 1));
result = JObject.Parse(str);
/* Add Headers from FHIR Server Response */
foreach (string key in fhirresp.Headers.Keys)
{
req.HttpContext.Response.Headers.Remove(key);
req.HttpContext.Response.Headers.Add(key, fhirresp.Headers[key].Value);
}
return(new JsonResult(result));
}
public static async Task <IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "post", "put", Route = "import/{resourceType?}")] HttpRequest req, string resourceType,
[EventHub("%EventHubName%", Connection = "EventHubConnection")] IAsyncCollector <EventData> outputEvents,
ILogger log)
{
log.LogInformation("FHIR Proxy - Import Function Invoked");
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
/* Get/update/check current bearer token to authenticate the proxy to the FHIR Server
* The following parameters must be defined in environment variables:
* To use Manged Service Identity or Service Client:
* FS_URL = the fully qualified URL to the FHIR Server
* FS_RESOURCE = the audience or resource for the FHIR Server for Azure API for FHIR should be https://azurehealthcareapis.com
* To use a Service Client Principal the following must also be specified:
* FS_TENANT_NAME = the GUID or UPN of the AAD tenant that is hosting FHIR Server Authentication
* FS_CLIENT_ID = the client or app id of the private client authorized to access the FHIR Server
* FS_SECRET = the client secret to pass to FHIR Server Authentication
*/
if (!string.IsNullOrEmpty(System.Environment.GetEnvironmentVariable("FS_RESOURCE")) && FHIRClient.isTokenExpired(_bearerToken))
{
lock (_lock)
{
if (FHIRClient.isTokenExpired(_bearerToken))
{
log.LogInformation($"Obtaining new OAUTH2 Bearer Token for access to FHIR Server");
_bearerToken = FHIRClient.GetOAUTH2BearerToken(System.Environment.GetEnvironmentVariable("FS_RESOURCE"), System.Environment.GetEnvironmentVariable("FS_TENANT_NAME"),
System.Environment.GetEnvironmentVariable("FS_CLIENT_ID"), System.Environment.GetEnvironmentVariable("FS_SECRET")).GetAwaiter().GetResult();
}
}
}
/*
* Create User Custom Headers these headers are passed to the FHIR Server to communicate credentials of the authorized user for each proxy call
* this is ensures accruate audit trails for FHIR server access. Note: This headers are honored by the Azure API for FHIR Server
*/
List <HeaderParm> auditheaders = new List <HeaderParm>();
auditheaders.Add(new HeaderParm("X-MS-AZUREFHIR-AUDIT-PROXY", "FHIREventProcessor-Import"));
/* Preserve FHIR Specific change control headers and include in the proxy call */
List <HeaderParm> customandrestheaders = new List <HeaderParm>();
foreach (string key in req.Headers.Keys)
{
string s = key.ToLower();
if (s.Equals("etag"))
{
customandrestheaders.Add(new HeaderParm(key, req.Headers[key].First()));
}
else if (s.StartsWith("if-"))
{
customandrestheaders.Add(new HeaderParm(key, req.Headers[key].First()));
}
}
/* Add User Audit Headers */
customandrestheaders.AddRange(auditheaders);
/* Get a FHIR Client instance to talk to the FHIR Server */
log.LogInformation($"Instanciating FHIR Client Proxy");
FHIRClient fhirClient = new FHIRClient(System.Environment.GetEnvironmentVariable("FS_URL"), _bearerToken);
//Check for transaction bundle
var result = fhirClient.SaveResource(resourceType, requestBody, "POST", customandrestheaders.ToArray());
if (result.StatusCode == HttpStatusCode.OK || result.StatusCode == HttpStatusCode.Created)
{
var fhirresp = JObject.Parse((string)result.Content);
if (fhirresp != null && ((string)fhirresp["resourceType"]).Equals("Bundle") && ((string)fhirresp["type"]).EndsWith("-response"))
{
JArray entries = (JArray)fhirresp["entry"];
foreach (JToken tok in entries)
{
JObject entryresp = (JObject)tok["response"];
var entrystatus = (string)entryresp["status"];
if (entrystatus.Equals("200") || entrystatus.Equals("201"))
{
var res = (JObject)tok["resource"];
string msg = "{\"effectedresource\":\"" + (string)res["resourceType"] + "\",\"id\":\"" + (string)res["id"] + "\"}";
log.LogInformation("Adding Event: " + msg);
EventData dt = new EventData(Encoding.UTF8.GetBytes(msg));
await outputEvents.AddAsync(dt);
}
}
}
else
{
string msg = "{\"effectedresource\":\"" + (string)fhirresp["resourceType"] + "\",\"id\":\"" + (string)fhirresp["id"] + "\"}";
log.LogInformation("Adding Event: " + msg);
EventData dt = new EventData(Encoding.UTF8.GetBytes(msg));
await outputEvents.AddAsync(dt);
}
return(new JsonResult(fhirresp));
}
string retval = (string)result.Content;
if (string.IsNullOrEmpty(retval))
{
retval = "{\"error\":\"Unexpected Result\"}";
}
var jr = new JsonResult(JObject.Parse(retval));
jr.StatusCode = (int)result.StatusCode;
return(jr);
}
private static string transformTransactionBundles(string requestBody, FHIRClient fsclient, ILogger log)
{
if (string.IsNullOrEmpty(requestBody))
{
return(requestBody);
}
JObject result = JObject.Parse(requestBody);
if (result == null || result["resourceType"] == null || result["type"] == null)
{
return(requestBody);
}
string rtt = (string)result["resourceType"];
string bt = (string)result["type"];
if (rtt.Equals("Bundle") && bt.Equals("transaction"))
{
log.LogInformation($"TransformBundleProcess: looks like a valid transaction bundle");
JArray entries = (JArray)result["entry"];
if (entries == null)
{
return(requestBody);
}
log.LogInformation($"TransformBundleProcess: Phase 1 searching for existing entries on FHIR Server...");
foreach (JToken tok in entries)
{
if (tok != null && tok["request"]["ifNoneExist"] != null)
{
string resource = (string)tok["request"]["url"];
string query = (string)tok["request"]["ifNoneExist"];
log.LogInformation($"TransformBundleProcess:Loading Resource {resource} with query {query}");
var r = fsclient.LoadResource(resource, query);
if (r.StatusCode == System.Net.HttpStatusCode.OK)
{
var rs = (JObject)r.Content;
if (rs != null && ((string)rs["resourceType"]).Equals("Bundle") && rs["entry"] != null)
{
JArray respentries = (JArray)rs["entry"];
string existingid = "urn:uuid:" + (string)respentries[0]["resource"]["id"];
string furl = (string)tok["fullUrl"];
if (!string.IsNullOrEmpty(furl))
{
requestBody.Replace(furl, existingid);
}
}
}
}
}
//reparse JSON with replacement of existing ids prepare to convert to Batch bundle with PUT to maintain relationships
Dictionary <string, string> convert = new Dictionary <string, string>();
result = JObject.Parse(requestBody);
result["type"] = "batch";
entries = (JArray)result["entry"];
foreach (JToken tok in entries)
{
string urn = (string)tok["fullUrl"];
if (!string.IsNullOrEmpty(urn) && urn.StartsWith("urn:uuid:") && tok["resource"] != null)
{
string rt = (string)tok["resource"]["resourceType"];
string rid = urn.Replace("urn:uuid:", "");
tok["resource"]["id"] = rid;
convert.Add(rid, rt);
tok["request"]["method"] = "PUT";
tok["request"]["url"] = $"{rt}?_id={rid}";
}
}
log.LogInformation($"TransformBundleProcess: Phase 2 Localizing {convert.Count} resource entries...");
string str = result.ToString();
foreach (string id1 in convert.Keys)
{
string r1 = convert[id1] + "/" + id1;
string f = "urn:uuid:" + id1;
str = str.Replace(f, r1);
}
return(str);
}
return(requestBody);
}
