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HTTP dump of Libre Link Up used in combination with FreeStyle Libre 3
@Mynuggets-dev
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Mynuggets-dev commented Jan 31, 2026 •
edited
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Hello everyone! I’m developing an application to present at a national competition here in Brazil on January 31st, but I’m running into an issue when trying to connect to the API. For some reason, I’m unable to authenticate and retrieve data. I always receive the error "No token returned", because the API never seems to return the authentication token from the server. Could someone please help me understand what might be wrong and how I can fix my code?

Thanks a lot!

@liubquanti @Mynuggets-dev @sgmoore @MrAda @gjkoolen @xfoguet @SteveCEvans @adamlounds

`const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
}

async function sha256(message: string) {
    const msgBuffer = new TextEncoder().encode(message);
    const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    return hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
}

Deno.serve(async (req) => {
  if (req.method === 'OPTIONS') return new Response('ok', { headers: corsHeaders })

  try {
    const { email, password, region = "ae" } = await req.json()

    if (!email || !password) throw new Error("Email e senha obrigatórios")

    const baseUrl = `https://api-${region}.libreview.io`

    const commonHeaders = {
      "product": "llu.android",
      "version": "4.16.0", 
      "accept-encoding": "gzip, deflate, br",
      "cache-control": "no-cache",
      "connection": "keep-alive",
      "content-type": "application/json",
      "pragma": "no-cache",
    }

    console.log(`[LibreFix] 1. Login em ${baseUrl}...`)

    const loginResp = await fetch(`${baseUrl}/llu/auth/login`, {
      method: "POST",
      headers: commonHeaders,
      body: JSON.stringify({ email, password })
    })

    if (!loginResp.ok) {
        throw new Error(`Erro Login: ${loginResp.status} - Verifique credenciais`)
    }

    const loginData = await loginResp.json()
    
    const token = loginData.data?.authTicket?.token
    const userId = loginData.data?.user?.id 

    if (!token || !userId) {
        throw new Error("Login falhou: Token ou User ID não retornados.")
    }

    const accountIdHash = await sha256(userId);
    
    console.log(`[LibreFix] Hash gerado: ${accountIdHash.substring(0, 10)}...`)

    const authHeaders = {
        ...commonHeaders,
        "Authorization": `Bearer ${token}`,
        "Account-Id": accountIdHash 
    }

    console.log("[LibreFix] 2. Buscando conexões...")
    const connResp = await fetch(`${baseUrl}/llu/connections`, {
      headers: authHeaders 
    })
    
    const connData = await connResp.json()
    
    if (!connData.data || connData.data.length === 0) {
        throw new Error("Nenhum sensor vinculado. Use uma conta de SEGUIDOR (LibreLinkUp).")
    }
    
    const patientId = connData.data[0].patientId

    console.log(`[LibreFix] 3. Buscando dados...`)
    const graphResp = await fetch(`${baseUrl}/llu/connections/${patientId}/graph`, {
      headers: authHeaders
    })
    
    const graphData = await graphResp.json()
    const measurements = graphData.data?.connection?.glucoseMeasurement?.measurementData

    if (!measurements || measurements.length === 0) {
        throw new Error("Conexão feita, mas sem dados recentes.")
    }

    const latest = measurements[measurements.length - 1]

    console.log("[LibreFix] SUCESSO!", latest.Value)

    return new Response(
      JSON.stringify({ 
        value: latest.Value, 
        trend: latest.TrendArrow, 
        date: latest.FactoryTimestamp,
        isHigh: latest.isHigh,
        isLow: latest.isLow
      }),
      { headers: { ...corsHeaders, 'Content-Type': 'application/json' }, status: 200 }
    )

  } catch (error) {
    const msg = error instanceof Error ? error.message : String(error)
    console.error("ERRO FATAL:", msg)
    return new Response(
      JSON.stringify({ error: msg }),
      { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    )
  }
})`

try something like this

  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Headers":
    "authorization, x-client-info, apikey, content-type",
  "Access-Control-Allow-Methods": "POST, OPTIONS",
};

async function sha256Hex(message: string) {
  const msgBuffer = new TextEncoder().encode(message);
  const hashBuffer = await crypto.subtle.digest("SHA-256", msgBuffer);
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  return hashArray.map((b) => b.toString(16).padStart(2, "0")).join("");
}

// Simple in-memory token cache (keyed by email+region)
// If you deploy on serverless with cold starts, use Deno KV or your DB.
type Session = {
  token: string;
  accountIdHash: string;
  userId: string;
  region: string;
  baseUrl: string;
  updatedAt: number;
};

const sessionCache = new Map<string, Session>();

function cacheKey(email: string, region: string) {
  return `${region}::${email.toLowerCase().trim()}`;
}

function commonHeaders() {
  return {
    product: "llu.android",
    version: "4.16.0",
    "accept-encoding": "gzip, deflate, br",
    "cache-control": "no-cache",
    connection: "keep-alive",
    "content-type": "application/json",
    pragma: "no-cache",
  } as Record<string, string>;
}

async function login(email: string, password: string, region: string): Promise<Session> {
  const baseUrl = `https://api-${region}.libreview.io`;

  const resp = await fetch(`${baseUrl}/llu/auth/login`, {
    method: "POST",
    headers: commonHeaders(),
    body: JSON.stringify({ email, password }),
  });

  if (!resp.ok) {
    // Avoid leaking details; keep it useful.
    throw new Error(`Erro Login: ${resp.status} - Verifique credenciais/região`);
  }

  const loginData = await resp.json();

  const token = loginData?.data?.authTicket?.token as string | undefined;
  const userId = loginData?.data?.user?.id as string | undefined;

  if (!token || !userId) {
    throw new Error("Login falhou: Token ou User ID não retornados.");
  }

  const accountIdHash = await sha256Hex(userId);

  return {
    token,
    userId,
    accountIdHash,
    region,
    baseUrl,
    updatedAt: Date.now(),
  };
}

async function authedFetch(
  session: Session,
  input: string,
  init: RequestInit,
  relogin: () => Promise<Session>,
): Promise<{ resp: Response; session: Session }> {
  const makeHeaders = (s: Session) => ({
    ...commonHeaders(),
    Authorization: `Bearer ${s.token}`,
    "Account-Id": s.accountIdHash,
    ...(init.headers ?? {}),
  });

  // First try
  let resp = await fetch(input, { ...init, headers: makeHeaders(session) });

  // Token invalid/expired: refresh once and retry
  if (resp.status === 401 || resp.status === 403) {
    const fresh = await relogin();
    resp = await fetch(input, { ...init, headers: makeHeaders(fresh) });
    return { resp, session: fresh };
  }

  return { resp, session };
}

Deno.serve(async (req) => {
  if (req.method === "OPTIONS") return new Response("ok", { headers: corsHeaders });

  try {
    const { email, password, region = "ae" } = await req.json();

    if (!email || !password) throw new Error("Email e senha obrigatórios");

    const key = cacheKey(email, region);

    // Get cached session or login
    let session = sessionCache.get(key);
    if (!session) {
      session = await login(email, password, region);
      sessionCache.set(key, session);
    }

    // Helper to re-login and update cache
    const relogin = async () => {
      const fresh = await login(email, password, region);
      sessionCache.set(key, fresh);
      return fresh;
    };

    // 1) Connections
    const connUrl = `${session.baseUrl}/llu/connections`;

    const connResult = await authedFetch(session, connUrl, { method: "GET" }, relogin);
    session = connResult.session;

    if (!connResult.resp.ok) {
      throw new Error(`Erro conexões: ${connResult.resp.status}`);
    }

    const connData = await connResult.resp.json();

    if (!Array.isArray(connData?.data) || connData.data.length === 0) {
      throw new Error("Nenhum sensor vinculado. Use conta SEGUIDOR (LibreLinkUp).");
    }

    const patientId = connData.data[0]?.patientId;
    if (!patientId) throw new Error("Conexão inválida: patientId ausente.");

    // 2) Graph
    const graphUrl = `${session.baseUrl}/llu/connections/${patientId}/graph`;

    const graphResult = await authedFetch(session, graphUrl, { method: "GET" }, relogin);
    session = graphResult.session;

    if (!graphResult.resp.ok) {
      throw new Error(`Erro dados: ${graphResult.resp.status}`);
    }

    const graphData = await graphResult.resp.json();

    const measurements =
      graphData?.data?.connection?.glucoseMeasurement?.measurementData;

    if (!Array.isArray(measurements) || measurements.length === 0) {
      throw new Error("Conexão feita, mas sem dados recentes.");
    }

    const latest = measurements[measurements.length - 1];

    return new Response(
      JSON.stringify({
        value: latest.Value,
        trend: latest.TrendArrow,
        date: latest.FactoryTimestamp,
        isHigh: latest.isHigh,
        isLow: latest.isLow,
      }),
      { headers: { ...corsHeaders, "Content-Type": "application/json" }, status: 200 },
    );
  } catch (error) {
    const msg = error instanceof Error ? error.message : String(error);
    return new Response(JSON.stringify({ error: msg }), {
      status: 400,
      headers: { ...corsHeaders, "Content-Type": "application/json" },
    });
  }
});

@Mynuggets-dev
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Mynuggets-dev commented Jan 31, 2026 •
edited
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image this is one i have been making and use to watch a friend i care for, i just compile the data from the raw ' current reading ' and log them every 1min 24/7

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