Merge pull request #693 from binwiederhier/html-emails

WIP: HTML emails
binwiederhier · Nov 16, 2023 · d0c2b00 · d0c2b00
2 parents 73eaf7b + 37091f2
commit d0c2b00
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diff --git a/docs/releases.md b/docs/releases.md
@@ -1287,6 +1287,7 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 **Bug fixes + maintenance:**
 
+* Support for HTML-only emails ([#690](https://github.com/binwiederhier/ntfy/issues/690)/[#693](https://github.com/binwiederhier/ntfy/pull/693), thanks to [@teastrainer](https://github.com/teastrainer) and [@CrazyWolf13](https://github.com/CrazyWolf13) for reporting)
 * Fix ACL issue with topic patterns containing underscores ([#840](https://github.com/binwiederhier/ntfy/issues/840), thanks to [@Joe-0237](https://github.com/Joe-0237) for reporting)
 * Re-add `tzdata` to Docker images for amd64 image ([#894](https://github.com/binwiederhier/ntfy/issues/894), [#307](https://github.com/binwiederhier/ntfy/pull/307))
 * Add special logic to ignore `Priority` header if it resembled a RFC 9218 value ([#851](https://github.com/binwiederhier/ntfy/pull/851)/[#895](https://github.com/binwiederhier/ntfy/pull/895), thanks to [@gusdleon](https://github.com/gusdleon), see also [#351](https://github.com/binwiederhier/ntfy/issues/351), [#353](https://github.com/binwiederhier/ntfy/issues/353), [#461](https://github.com/binwiederhier/ntfy/issues/461))

diff --git a/go.mod b/go.mod
@@ -1,25 +1,27 @@
 module heckel.io/ntfy
 
-go 1.18
+go 1.21
+
+toolchain go1.21.3
 
 require (
 	cloud.google.com/go/firestore v1.14.0 // indirect
-	cloud.google.com/go/storage v1.34.1 // indirect
+	cloud.google.com/go/storage v1.35.1 // indirect
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.3 // indirect
 	github.com/emersion/go-smtp v0.18.0
 	github.com/gabriel-vasile/mimetype v1.4.3
 	github.com/gorilla/websocket v1.5.1
 	github.com/mattn/go-sqlite3 v1.14.18
 	github.com/olebedev/when v1.0.0
-	github.com/stretchr/testify v1.8.1
+	github.com/stretchr/testify v1.8.4
 	github.com/urfave/cli/v2 v2.25.7
-	golang.org/x/crypto v0.14.0
-	golang.org/x/oauth2 v0.13.0 // indirect
+	golang.org/x/crypto v0.15.0
+	golang.org/x/oauth2 v0.14.0 // indirect
 	golang.org/x/sync v0.5.0
-	golang.org/x/term v0.13.0
+	golang.org/x/term v0.14.0
 	golang.org/x/time v0.4.0
-	google.golang.org/api v0.149.0
+	google.golang.org/api v0.150.0
 	gopkg.in/yaml.v2 v2.4.0
 )
 
@@ -30,6 +32,7 @@ require github.com/pkg/errors v0.9.1 // indirect
 require (
 	firebase.google.com/go/v4 v4.12.1
 	github.com/SherClockHolmes/webpush-go v1.3.0
+	github.com/microcosm-cc/bluemonday v1.0.26
 	github.com/prometheus/client_golang v1.17.0
 	github.com/stripe/stripe-go/v74 v74.30.0
 )
@@ -42,10 +45,11 @@ require (
 	cloud.google.com/go/longrunning v0.5.4 // indirect
 	github.com/AlekSi/pointer v1.2.0 // indirect
 	github.com/MicahParks/keyfunc v1.9.0 // indirect
+	github.com/aymerick/douceur v0.2.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead // indirect
+	github.com/emersion/go-sasl v0.0.0-20231106173351-e73c9f7bad43 // indirect
 	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
@@ -54,6 +58,7 @@ require (
 	github.com/google/uuid v1.4.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.0 // indirect
+	github.com/gorilla/css v1.0.1 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
@@ -64,15 +69,15 @@ require (
 	github.com/stretchr/objx v0.5.0 // indirect
 	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
 	go.opencensus.io v0.24.0 // indirect
-	golang.org/x/net v0.17.0 // indirect
+	golang.org/x/net v0.18.0 // indirect
 	golang.org/x/sys v0.14.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028 // indirect
 	google.golang.org/appengine v1.6.8 // indirect
 	google.golang.org/appengine/v2 v2.0.5 // indirect
-	google.golang.org/genproto v0.0.0-20231030173426-d783a09b4405 // indirect
-	google.golang.org/genproto/googleapis/api v0.0.0-20231030173426-d783a09b4405 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20231030173426-d783a09b4405 // indirect
+	google.golang.org/genproto v0.0.0-20231106174013-bbf56f31fb17 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20231106174013-bbf56f31fb17 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20231106174013-bbf56f31fb17 // indirect
 	google.golang.org/grpc v1.59.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

diff --git a/go.sum b/go.sum
@@ -13,6 +13,8 @@ cloud.google.com/go/longrunning v0.5.4 h1:w8xEcbZodnA2BbW6sVirkkoC+1gP8wS57EUUgG
 cloud.google.com/go/longrunning v0.5.4/go.mod h1:zqNVncI0BOP8ST6XQD1+VcvuShMmq7+xFSzOL++V0dI=
 cloud.google.com/go/storage v1.34.1 h1:H2Af2dU5J0PF7A5B+ECFIce+RqxVnrVilO+cu0TS3MI=
 cloud.google.com/go/storage v1.34.1/go.mod h1:VN1ElqqvR9adg1k9xlkUJ55cMOP1/QjnNNuT5xQL6dY=
+cloud.google.com/go/storage v1.35.1 h1:B59ahL//eDfx2IIKFBeT5Atm9wnNmj3+8xG/W4WB//w=
+cloud.google.com/go/storage v1.35.1/go.mod h1:M6M/3V/D3KpzMTJyPOR/HU6n2Si5QdaXYEsng2xgOs8=
 firebase.google.com/go/v4 v4.12.1 h1:tDNvobifGsx/1HSFLnM0fmNfx/CDZSgsTO2KhZtgpcs=
 firebase.google.com/go/v4 v4.12.1/go.mod h1:60c36dWLK4+j05Vw5XMllek3b3PCynU3BfI46OSwsUE=
 github.com/AlekSi/pointer v1.2.0 h1:glcy/gc4h8HnG2Z3ZECSzZ1IX1x2JxRVuDzaJwQE0+w=
@@ -24,6 +26,8 @@ github.com/MicahParks/keyfunc v1.9.0 h1:lhKd5xrFHLNOWrDc4Tyb/Q1AJ4LCzQ48GVJyVIID
 github.com/MicahParks/keyfunc v1.9.0/go.mod h1:IdnCilugA0O/99dW+/MkvlyrsX8+L8+x95xuVNtM5jw=
 github.com/SherClockHolmes/webpush-go v1.3.0 h1:CAu3FvEE9QS4drc3iKNgpBWFfGqNthKlZhp5QpYnu6k=
 github.com/SherClockHolmes/webpush-go v1.3.0/go.mod h1:AxRHmJuYwKGG1PVgYzToik1lphQvDnqFYDqimHvwhIw=
+github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
+github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
@@ -40,6 +44,8 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead h1:fI1Jck0vUrXT8bnphprS1EoVRe2Q5CKCX8iDlpqjQ/Y=
 github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
+github.com/emersion/go-sasl v0.0.0-20231106173351-e73c9f7bad43 h1:hH4PQfOndHDlpzYfLAAfl63E8Le6F2+EL/cdhlkyRJY=
+github.com/emersion/go-sasl v0.0.0-20231106173351-e73c9f7bad43/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/emersion/go-smtp v0.17.0 h1:tq90evlrcyqRfE6DSXaWVH54oX6OuZOQECEmhWBMEtI=
 github.com/emersion/go-smtp v0.17.0/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
@@ -89,15 +95,22 @@ github.com/googleapis/enterprise-certificate-proxy v0.3.2 h1:Vie5ybvEvT75RniqhfF
 github.com/googleapis/enterprise-certificate-proxy v0.3.2/go.mod h1:VLSiSSBs/ksPL8kq3OBOQ6WRI2QnaFynd1DCjZ62+V0=
 github.com/googleapis/gax-go/v2 v2.12.0 h1:A+gCJKdRfqXkr+BIRGtZLibNXf0m1f9E4HG56etFpas=
 github.com/googleapis/gax-go/v2 v2.12.0/go.mod h1:y+aIqrI5eb1YGMVJfuV3185Ts/D7qKpsEkdD5+I6QGU=
+github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
+github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
+github.com/gorilla/css v1.0.1 h1:ntNaBIghp6JmvWnxbZKANoLyuXTPZ4cAMlo6RyhlbO8=
+github.com/gorilla/css v1.0.1/go.mod h1:BvnYkspnSzMmwRK+b8/xgNPLiIuNZr6vbZBTPQ2A3b0=
 github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/QY=
 github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/mattn/go-sqlite3 v1.14.18 h1:JL0eqdCOq6DJVNPSvArO/bIV9/P7fbGrV00LZHc+5aI=
 github.com/mattn/go-sqlite3 v1.14.18/go.mod h1:2eHXhiwb8IkHr+BDWZGa96P6+rkvnG63S2DGjv9HUNg=
+github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 h1:jWpvCLoY8Z/e3VKvlsiIGKtc+UG6U5vzxaoagmhXfyg=
 github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0/go.mod h1:QUyp042oQthUoa9bqDv0ER0wrtXnBruoNd7aNjkbP+k=
+github.com/microcosm-cc/bluemonday v1.0.26 h1:xbqSvqzQMeEHCqMi64VAs4d8uy6Mequs3rQ0k/Khz58=
+github.com/microcosm-cc/bluemonday v1.0.26/go.mod h1:JyzOCs9gkyQyjs+6h10UEVSe02CGwkhd72Xdqh78TWs=
 github.com/olebedev/when v1.0.0 h1:T2DZCj8HxUhOVxcqaLOmzuTr+iZLtMHsZEim7mjIA2w=
 github.com/olebedev/when v1.0.0/go.mod h1:T0THb4kP9D3NNqlvCwIG4GyUioTAzEhB4RNVzig/43E=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -125,6 +138,8 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/stripe/stripe-go/v74 v74.30.0 h1:0Kf0KkeFnY7iRhOwvTerX0Ia1BRw+eV1CVJ51mGYAUY=
 github.com/stripe/stripe-go/v74 v74.30.0/go.mod h1:f9L6LvaXa35ja7eyvP6GQswoaIPaBRvGAimAO+udbBw=
 github.com/urfave/cli/v2 v2.25.7 h1:VAzn5oq403l5pHjc4OhD54+XGO9cdKVL/7lDjF+iKUs=
@@ -140,6 +155,8 @@ golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.9.0/go.mod h1:yrmDGqONDYtNj3tH8X9dzUun2m2lzPa9ngI6/RUPGR0=
 golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
 golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
@@ -160,9 +177,13 @@ golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
 golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
 golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
+golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.13.0 h1:jDDenyj+WgFtmV3zYVoi8aE2BwtXFLWOA67ZfNWftiY=
 golang.org/x/oauth2 v0.13.0/go.mod h1:/JMhi4ZRXAf4HG9LiNmxvk+45+96RUlVThiH8FzNBn0=
+golang.org/x/oauth2 v0.14.0 h1:P0Vrf/2538nmC0H+pEQ3MNFRRnVR7RlqyVw+bvm26z0=
+golang.org/x/oauth2 v0.14.0/go.mod h1:lAtNWgaWfL4cm7j2OV8TxGi9Qb7ECORx8DktCY74OwM=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -189,6 +210,8 @@ golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
 golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
 golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
 golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
+golang.org/x/term v0.14.0 h1:LGK9IlZ8T9jvdy6cTdfKUCltatMFOehAQo9SRC46UQ8=
+golang.org/x/term v0.14.0/go.mod h1:TySc+nGkYR6qt8km8wUhuFRTVSMIX3XPR58y2lC8vww=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
@@ -214,6 +237,8 @@ golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028 h1:+cNy6SZtPcJQH3LJVLOSm
 golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028/go.mod h1:NDW/Ps6MPRej6fsCIbMTohpP40sJ/P/vI1MoTEGwX90=
 google.golang.org/api v0.149.0 h1:b2CqT6kG+zqJIVKRQ3ELJVLN1PwHZ6DJ3dW8yl82rgY=
 google.golang.org/api v0.149.0/go.mod h1:Mwn1B7JTXrzXtnvmzQE2BD6bYZQ8DShKZDZbeN9I7qI=
+google.golang.org/api v0.150.0 h1:Z9k22qD289SZ8gCJrk4DrWXkNjtfvKAUo/l1ma8eBYE=
+google.golang.org/api v0.150.0/go.mod h1:ccy+MJ6nrYFgE3WgRx/AMXOxOmU8Q4hSa+jjibzhxcg=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.6.8 h1:IhEN5q69dyKagZPYMSdIjS2HqprW324FRQZJcGqPAsM=
@@ -225,10 +250,16 @@ google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
 google.golang.org/genproto v0.0.0-20231030173426-d783a09b4405 h1:I6WNifs6pF9tNdSob2W24JtyxIYjzFB9qDlpUC76q+U=
 google.golang.org/genproto v0.0.0-20231030173426-d783a09b4405/go.mod h1:3WDQMjmJk36UQhjQ89emUzb1mdaHcPeeAh4SCBKznB4=
+google.golang.org/genproto v0.0.0-20231106174013-bbf56f31fb17 h1:wpZ8pe2x1Q3f2KyT5f8oP/fa9rHAKgFPr/HZdNuS+PQ=
+google.golang.org/genproto v0.0.0-20231106174013-bbf56f31fb17/go.mod h1:J7XzRzVy1+IPwWHZUzoD0IccYZIrXILAQpc+Qy9CMhY=
 google.golang.org/genproto/googleapis/api v0.0.0-20231030173426-d783a09b4405 h1:HJMDndgxest5n2y77fnErkM62iUsptE/H8p0dC2Huo4=
 google.golang.org/genproto/googleapis/api v0.0.0-20231030173426-d783a09b4405/go.mod h1:oT32Z4o8Zv2xPQTg0pbVaPr0MPOH6f14RgXt7zfIpwg=
+google.golang.org/genproto/googleapis/api v0.0.0-20231106174013-bbf56f31fb17 h1:JpwMPBpFN3uKhdaekDpiNlImDdkUAyiJ6ez/uxGaUSo=
+google.golang.org/genproto/googleapis/api v0.0.0-20231106174013-bbf56f31fb17/go.mod h1:0xJLfVdJqpAPl8tDg1ujOCGzx6LFLttXT5NhllGOXY4=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20231030173426-d783a09b4405 h1:AB/lmRny7e2pLhFEYIbl5qkDAUt2h0ZRO4wGPhZf+ik=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20231030173426-d783a09b4405/go.mod h1:67X1fPuzjcrkymZzZV1vvkFeTn2Rvc6lYF9MYFGCcwE=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20231106174013-bbf56f31fb17 h1:Jyp0Hsi0bmHXG6k9eATXoYtjd6e2UzZ1SCn/wIupY14=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20231106174013-bbf56f31fb17/go.mod h1:oQ5rr10WTTMvP4A36n8JpR1OrO1BEiV4f78CneXZxkA=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
 google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
 google.golang.org/grpc v1.25.1/go.mod h1:c3i+UQWmh7LiEpx4sFZnkU36qjEYZ0imhYfXVyQciAY=

diff --git a/server/smtp_server.go b/server/smtp_server.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/emersion/go-smtp"
+	"github.com/microcosm-cc/bluemonday"
 	"io"
 	"mime"
 	"mime/multipart"
@@ -14,6 +15,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/mail"
+	"regexp"
 	"strings"
 	"sync"
 )
@@ -27,6 +29,11 @@ var (
 	errUnsupportedContentType = errors.New("unsupported content type")
 )
 
+var (
+	onlySpacesRegex          = regexp.MustCompile(`(?m)^\s+$`)
+	consecutiveNewLinesRegex = regexp.MustCompile(`\n{3,}`)
+)
+
 const (
 	maxMultipartDepth = 2
 )
@@ -232,37 +239,66 @@ func readMailBody(body io.Reader, header mail.Header) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	if strings.ToLower(contentType) == "text/plain" {
-		return readPlainTextMailBody(body, header.Get("Content-Transfer-Encoding"))
-	} else if strings.HasPrefix(strings.ToLower(contentType), "multipart/") {
-		return readMultipartMailBody(body, params, 0)
+	canonicalContentType := strings.ToLower(contentType)
+	if canonicalContentType == "text/plain" || canonicalContentType == "text/html" {
+		return readTextMailBody(body, canonicalContentType, header.Get("Content-Transfer-Encoding"))
+	} else if strings.HasPrefix(canonicalContentType, "multipart/") {
+		return readMultipartMailBody(body, params)
 	}
 	return "", errUnsupportedContentType
 }
 
-func readMultipartMailBody(body io.Reader, params map[string]string, depth int) (string, error) {
+func readMultipartMailBody(body io.Reader, params map[string]string) (string, error) {
+	parts := make(map[string]string)
+	if err := readMultipartMailBodyParts(body, params, 0, parts); err != nil && err != io.EOF {
+		return "", err
+	} else if s, ok := parts["text/plain"]; ok {
+		return s, nil
+	} else if s, ok := parts["text/html"]; ok {
+		return s, nil
+	}
+	return "", io.EOF
+}
+
+func readMultipartMailBodyParts(body io.Reader, params map[string]string, depth int, parts map[string]string) error {
 	if depth >= maxMultipartDepth {
-		return "", errMultipartNestedTooDeep
+		return errMultipartNestedTooDeep
 	}
 	mr := multipart.NewReader(body, params["boundary"])
 	for {
 		part, err := mr.NextPart()
 		if err != nil { // may be io.EOF
-			return "", err
+			return err
 		}
 		partContentType, partParams, err := mime.ParseMediaType(part.Header.Get("Content-Type"))
 		if err != nil {
-			return "", err
+			return err
 		}
-		if strings.ToLower(partContentType) == "text/plain" {
-			return readPlainTextMailBody(part, part.Header.Get("Content-Transfer-Encoding"))
+		canonicalPartContentType := strings.ToLower(partContentType)
+		if canonicalPartContentType == "text/plain" || canonicalPartContentType == "text/html" {
+			s, err := readTextMailBody(part, canonicalPartContentType, part.Header.Get("Content-Transfer-Encoding"))
+			if err != nil {
+				return err
+			}
+			parts[canonicalPartContentType] = s
 		} else if strings.HasPrefix(strings.ToLower(partContentType), "multipart/") {
-			return readMultipartMailBody(part, partParams, depth+1)
+			if err := readMultipartMailBodyParts(part, partParams, depth+1, parts); err != nil {
+				return err
+			}
 		}
 		// Continue with next part
 	}
 }
 
+func readTextMailBody(reader io.Reader, contentType, transferEncoding string) (string, error) {
+	if contentType == "text/plain" {
+		return readPlainTextMailBody(reader, transferEncoding)
+	} else if contentType == "text/html" {
+		return readHTMLMailBody(reader, transferEncoding)
+	}
+	return "", fmt.Errorf("unsupported content type: %s", contentType)
+}
+
 func readPlainTextMailBody(reader io.Reader, transferEncoding string) (string, error) {
 	if strings.ToLower(transferEncoding) == "base64" {
 		reader = base64.NewDecoder(base64.StdEncoding, reader)
@@ -275,3 +311,21 @@ func readPlainTextMailBody(reader io.Reader, transferEncoding string) (string, e
 	}
 	return string(body), nil
 }
+
+func readHTMLMailBody(reader io.Reader, transferEncoding string) (string, error) {
+	body, err := readPlainTextMailBody(reader, transferEncoding)
+	if err != nil {
+		return "", err
+	}
+	stripped := bluemonday.
+		StrictPolicy().
+		AddSpaceWhenStrippingTag(true).
+		Sanitize(body)
+	return removeExtraEmptyLines(stripped), nil
+}
+
+func removeExtraEmptyLines(s string) string {
+	s = onlySpacesRegex.ReplaceAllString(s, "")
+	s = consecutiveNewLinesRegex.ReplaceAllString(s, "\n\n")
+	return s
+}