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/rfid endpoint - Serve with chunked response #280

Merged
merged 8 commits into from
Dec 29, 2023
Merged

/rfid endpoint - Serve with chunked response #280

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3e2b0f6
rfid chunked response
tueddy Dec 12, 2023
788d4ff
fixes
tueddy Dec 13, 2023
0d9c7b3
make clang check happy
tueddy Dec 13, 2023
b080121
endpoint /rfid returns tag details (as before)
tueddy Dec 14, 2023
86fa4f4
clang
tueddy Dec 14, 2023
871df02
fix error: inconsistent types 'int' and 'unsigned int' deduced for la…
tueddy Dec 14, 2023
403d2e5
nvsIndex is size_t
tueddy Dec 29, 2023
9c3b512
ids->ids-only
tueddy Dec 29, 2023
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105 changes: 83 additions & 22 deletions src/Web.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -457,6 +457,7 @@ void webserverStart(void) {

// RFID
wServer.on("/rfid", HTTP_GET, handleGetRFIDRequest);
wServer.addRewrite(new OneParamRewrite("/rfid/ids", "/rfid?ids=true"));
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I propose, that the parameter ids should be called something like ids-only. We have a parapemeter id already, so a mixup could easily happen.

Suggested change
wServer.addRewrite(new OneParamRewrite("/rfid/ids", "/rfid?ids=true"));
wServer.addRewrite(new OneParamRewrite("/rfid/ids-only", "/rfid?ids-only=true"));

wServer.addHandler(new AsyncCallbackJsonWebHandler("/rfid", handlePostRFIDRequest));
wServer.addRewrite(new OneParamRewrite("/rfid/{id}", "/rfid?id={id}"));
wServer.on("/rfid", HTTP_DELETE, handleDeleteRFIDRequest);
Expand Down Expand Up @@ -1685,34 +1686,94 @@ bool DumpNvsToJSONCallback(const char *key, void *data) {
return tagIdToJSON(key, obj);
}

// callback for writing a NVS entry to list
bool DumpNvsToArrayCallback(const char *key, void *data) {
std::vector<String> *keys = (std::vector<String> *) data;
keys->push_back(key);
return true;
}

static String tagIdToJsonStr(const char *key, const bool nameOnly) {
if (nameOnly) {
return "\"" + String(key) + "\"";
} else {
StaticJsonDocument<512> doc;
JsonObject entry = doc.createNestedObject(key);
if (!tagIdToJSON(key, entry)) {
return "";
}
String serializedJsonString;
serializeJson(entry, serializedJsonString);
return serializedJsonString;
}
}

// Handles rfid-assignments requests (GET)
// /rfid returns an array of tag-id keys
// /rfid/details returns an array of tag-ids and details. Optional GET param "id" to list only a single assignment.
static void handleGetRFIDRequest(AsyncWebServerRequest *request) {

String tagId = "";

if (request->hasParam("id")) {
tagId = request->getParam("id")->value();
}
if (tagId == "") {
// return all RFID assignments
AsyncJsonResponse *response = new AsyncJsonResponse(true, 8192);
JsonArray Arr = response->getRoot();
if (listNVSKeys("rfidTags", &Arr, DumpNvsToJSONCallback)) {
response->setLength();
request->send(response);
} else {
request->send(500, "error reading entries from NVS");
}
} else {
if (gPrefsRfid.isKey(tagId.c_str())) {
// return single RFID assignment
AsyncJsonResponse *response = new AsyncJsonResponse(false);
JsonObject obj = response->getRoot();
tagIdToJSON(tagId, obj);
response->setLength();
request->send(response);
} else {
// RFID assignment not found
request->send(404);
}

if ((tagId != "") && gPrefsRfid.isKey(tagId.c_str())) {
// return single RFID entry
String json = tagIdToJsonStr(tagId.c_str(), true);
request->send(200, "application/json", json);
return;
}
// get tag details or just an array of id's
bool idsOnly = request->hasParam("ids");
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See comment in line #460. Here we just grab the parameter

Suggested change
bool idsOnly = request->hasParam("ids");
const bool idsOnly = request->hasParam("ids-only");


std::vector<String> nvsKeys {};
static uint16_t nvsIndex;
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See comment on line 1747.

Suggested change
static uint16_t nvsIndex;

nvsKeys.clear();
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Not needed since nvsKeys was just created (since it's not a static variable any more), so it's already empty.

Suggested change
nvsKeys.clear();

// Dumps all RFID-keys from NVS into key array
listNVSKeys("rfidTags", &nvsKeys, DumpNvsToArrayCallback);
if (nvsKeys.size() == 0) {
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Would not need this special handling for size == 0 if in the chunked response there was no special handling for the first tag.

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Writing the first tag there is no comma in JSON, it is starting with the second entry.
That's is the reason to handle the special case size==0 here and not even start a chunked response.

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Not starting the chunked response in the first place is probably a good idea.

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This looks ok for me, we do not start the chunked response here (just send back an empty array and return)

// no entries
request->send(200, "application/json", "[]");
return;
}
// construct chunked repsonse
nvsIndex = 0;
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see 1747

Suggested change
nvsIndex = 0;

AsyncWebServerResponse *response = request->beginChunkedResponse("application/json",
[nvsKeys = std::move(nvsKeys), idsOnly](uint8_t *buffer, size_t maxLen, size_t index) {
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Fix the return type of the lambda to size_t here (so that we can write return 0).

Suggested change
[nvsKeys = std::move(nvsKeys), idsOnly](uint8_t *buffer, size_t maxLen, size_t index) {
[nvsKeys = std::move(nvsKeys), idsOnly](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {

maxLen = maxLen >> 1; // some sort of bug with actual size available, reduce the len
size_t len = 0;
String json;
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we can move nvsIndex into the lambda here. Also nvsIndex should have the same type as std::vector::size().

Suggested change
String json;
static size_t nvsIndex = 0;
String json;


if (nvsIndex == 0) {
// start, write first tag
json = tagIdToJsonStr(nvsKeys[nvsIndex].c_str(), idsOnly);
if (json.length() >= maxLen) {
Log_Println("/rfid: Buffer too small", LOGLEVEL_ERROR);
return len;
}
len += snprintf(((char *) buffer), maxLen - len, "[%s", json.c_str());
nvsIndex++;
}
while (nvsIndex < nvsKeys.size()) {
// write tags as long we have enough room
json = tagIdToJsonStr(nvsKeys[nvsIndex].c_str(), idsOnly);
if ((len + json.length()) >= maxLen) {
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This should be only >, maxLen is the length of the buffer, not an index.

Suggested change
if ((len + json.length()) >= maxLen) {
if ((len + json.length()) > maxLen) {

break;
}
len += snprintf(((char *) buffer + len), maxLen - len, ",%s", json.c_str());
nvsIndex++;
}
if (nvsIndex == nvsKeys.size()) {
// finish
len += snprintf(((char *) buffer + len), maxLen - len, "]");
nvsIndex++;
}
Comment on lines +1771 to +1772
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We are finished here, so we can clean up here. (see comment on line 1775 regarding nvsKeys)

Suggested change
nvsIndex++;
}
nvsIndex++;
} else if (nvsIndex > nvsKeys.size()) {
nvsIndex = 0;
return 0;
}

return len;
});
nvsKeys.clear();
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I just saw, that we are accessing nvsKeys here. Since we called std::move on the variable, nvsKeys does not hold the array any more. As soons as the lambds is finished, the nvsKeys will go out of scope and it'll be destoryed.

Suggested change
nvsKeys.clear();

request->send(response);
}

static void handlePostRFIDRequest(AsyncWebServerRequest *request, JsonVariant &json) {
Expand Down