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Fix Emscripten request cancellation #182

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Fix Emscripten request cancellation #182

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29 changes: 19 additions & 10 deletions src/windy/platforms/emscripten/platform.nim
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,6 @@ type
requestBody: string
deadline: float64
startTime: float64
canceled: bool
completed: bool

onError: HttpErrorCallback
Expand Down Expand Up @@ -101,6 +100,13 @@ proc close*(window: Window) =
proc closeRequested*(window: Window): bool =
return false

proc abortFetch(state: EmsHttpRequestState) =
let fetch = state.fetch
if fetch == nil:
return
state.fetch = nil
emscripten_fetch_close(fetch)

proc pollHttp() =
## Poll HTTP requests.
let now = epochTime()
Expand All @@ -109,6 +115,7 @@ proc pollHttp() =
if state.completed: continue
if state.deadline > 0 and state.deadline <= now:
state.completed = true
state.abortFetch()
if state.onError != nil:
state.onError("Deadline exceeded")
var expiredSockets: seq[WebSocketHandle]
Expand Down Expand Up @@ -711,8 +718,10 @@ proc getState(fetch: ptr emscripten_fetch_t): EmsHttpRequestState =

proc onFetchSuccess(fetch: ptr emscripten_fetch_t) {.cdecl.} =
let state = getState(fetch)
if state == nil: return
if state == nil or state.completed:
return
state.completed = true
state.fetch = nil
var response = HttpResponse()
response.code = int(fetch.status)
if fetch.numBytes > 0 and fetch.data != nil:
Expand All @@ -726,8 +735,10 @@ proc onFetchSuccess(fetch: ptr emscripten_fetch_t) {.cdecl.} =

proc onFetchError(fetch: ptr emscripten_fetch_t) {.cdecl.} =
let state = getState(fetch)
if state == nil: return
if state == nil or state.completed:
return
state.completed = true
state.fetch = nil
if state.onError != nil:
var msg = $fetch.status & " "
for c in fetch.statusText:
Expand All @@ -738,7 +749,7 @@ proc onFetchError(fetch: ptr emscripten_fetch_t) {.cdecl.} =

proc onFetchProgress(fetch: ptr emscripten_fetch_t) {.cdecl.} =
let state = getState(fetch)
if state == nil: return
if state == nil or state.completed: return
if state.onDownloadProgress != nil:
let completed = int(fetch.dataOffset + fetch.numBytes)
let total = (if fetch.totalBytes == 0: -1 else: int(fetch.totalBytes))
Expand Down Expand Up @@ -796,17 +807,15 @@ proc startHttpRequest*(
# Headers array (optional): omit for now to avoid pointer array complexities
attr.requestHeaders = nil

discard emscripten_fetch(addr attr, url.cstring)
state.fetch = emscripten_fetch(addr attr, url.cstring)
result = handle

proc cancel*(handle: HttpRequestHandle) {.raises: [].} =
## Cancel an HTTP request.
let state = httpRequests.getOrDefault(handle, nil)
if state == nil: return
state.canceled = true
# There is no direct cancel from C API here; closing will abort if still active
if state.fetch != nil:
emscripten_fetch_close(state.fetch)
if state == nil or state.completed: return
state.completed = true
state.abortFetch()

proc deadline*(handle: HttpRequestHandle): float64 =
## Get the deadline of an HTTP request.
Expand Down